Browning M1919A4 machine gun.

By Robert G. Segel

The Browning M1919A4 air-cooled machine gun in .30-06 was the standard rifle caliber belt fed machine gun of the United States for three decades from the 1930s to the 1960s. It was the main infantry machine gun during World War II and Korea and saw initial service in Viet Nam until replaced by the M60 General Purpose Machine Gun.

Produced in the tens of thousands by many manufacturers it saw service in every theater of war. A simple spare parts roll was developed in the mid-1930s for the gunners to carry with them to maintain their weapon in working order providing key spare parts that could be easily replaced if the original became worn, damaged or broken.

The M-13 Spare Parts Roll is a canvas carrier with a braided canvas carrying handle that folds in on itself four times and is closed with a simple snap. When unfolded, a series of nine pockets, each numbered, present themselves each containing one or more spare parts. No tools are present in this roll. The numbered pockets and their contents are listed below.

Spare parts and placement in appropriate pockets.

Pocket #1:
1 Firing Pin Assembly (1-1)

Pocket #2:
1 Trigger (2-1)
1 Cover Extractor Spring (2-2)
1 Belt Holding Pawl Pin (2-3)
1 Belt Feed Lever (2-4)

Pocket #3:
Contains a canvas Envelope, Small Parts, M1, No. 1 (3-1) with contents:
1 Driving Spring (3-2)

Pocket #4:
1 Extractor Assembly (4-1)

Pocket #5:
Contains a canvas Envelope, Small Parts, M1, No. 2 (5-1) with contents:
1 Sear (5-2);
2 Buffer Discs (5-3);
3 Sear Spring Assemblies (5-4);
1 Belt Feed Lever Pivot Assembly (5-5);
2 Breech Lock Assembly Pins (5-6)

Pocket #6:
1 Accelerator (6-1)

Pocket #7:
Can, Tubular (not shown) with contents:
2 Barrel Locking Pins (7-1);
1 shown of 4 Ejector Pins (7-2);
2 shown of 12 Breech Lock Pin Springs (7-3)
1 Spring (7-4)
1 shown of 2 Firing Pin Spring Pins (7-5)
1 Trigger Pin Spring (7-6)
1 Ejector (7-7)
1 Trigger Pin (7-8)

Pocket # 8:
1 Belt Feed Slide (8-1)
1 Belt Feed Spring (8-2)
1 Belt Feed Pin Assembly (8-3)

Pocket #9:
1 Bolt Handle (9-1)

Czech ZB26 light machine gun.

By Robert G. Segel

People in the general populace don’t think of Czechoslovakia as an international arms maker of high quality products with a long history of innovation. But those familiar with the world of firearms know that Czechoslovakia has a well-earned reputation of not only producing quality weapons, but researching, developing and pioneering new systems. One such system was the ZB26. This weapon proved to be of such a step forward for a man-portable, full automatic weapon, that the British, upon testing, were so impressed that they licensed the manufacture of the weapon that was then known as the Bren gun; a weapon that served the British and their Commonwealth nations for decades.

The Czech ZB26 gunner’s kit is made of canvas with leather straps that folds in on itself for carrying measuring approximately 11 inches long x 7 inches wide x 1.5 inches thick. Once fully unfolded, leather pockets hold all of the various tools needed to maintain the weapon in proper working order. On one end is a pocket that contains spare parts for the weapon that may wear or break and are easily replaceable by the gunner.

MG11 Swiss Maxim.

By Robert G. Segel

The Swiss Maxim MG11 is considered by many as the Swiss watch of Maxim machine guns. Manufactured in Switzerland by Waffenfabrik Bern, the MG11 is noted for its precision manufacturing guaranteeing the utmost reliability in both form and function.

Each Swiss Maxim gun was issued a gunner’s kit with tools, cleaning components and key spare parts to keep the gun operating under all conditions with the ability to repair or replace certain vital parts by the gun team.

The metal gunner’s kit measures approximately 13.5 x 11.5 x 3.75 inches and is top opening with a single hinged locking clasp to the front. It also has two handles for carrying in either a vertical or horizontal manner. Wood compartments within the box allow for an orderly display and easy access to the contents. Small parts are contained in a leather pouch with a draw string.

1. Swiss Maxim MG11 compartmentalized gunner’s spare parts and tool box.
2. Three-piece cleaning rod
3. Galvanized tin 1 liter oil
container with handle
4. Two sheets of fine grit paper
5. Pliers
6. Brass drift
7. Steel drift
8. Punch 4mm
9. Punch 2mm
10. Small chisel
11. Screwdriver
12. Brass head hammer
13. Soft cleaning brush
14. Half-round file
15. Roll of barrel packing string
16. Bundle of cleaning cloths
17. Brass cleaning rod jag
18. Cleaning rod bore brush
19. Lifters (two)
20. Combination tool
21. Leather pouch with draw string (items 22 through 39 are contained in the leather pouch)
22. Firing pins (two)
23. Safety sear (complete)
24. Top cover springs (two)
25. Firing pin spring
26. Tumbler
27. Gib
28. Wire ring containing an assortment of 12 (6 pairs) of different length and diameter cotter pins
29. Extractor spring
30. Cleaning rod chamber brush
31. Side lever axis pin (two)
32. Trigger sear axis pin (three)
33. Side lever axis split pin
34. Safety-sear pin
35. Gib spring
36. Length of thin steel wire
37. Safety-sear springs (two)
38. Upper feed pawl springs (two)
39. Length of thin copper wire

By Robert G. Segel

Designed by Vasily Degtyaryov in 1927, the Russian DP28 was the primary light machine gun of the Red Army during World War II. Man portable with a distinctive 47-round pan magazine, the DP28 was produced in the hundreds of thousands of units and proved itself throughout its service life as a reliable and rugged weapon.

Whether from wear, breakage or battle damage, DP28 gunners carried a gunner’s kit with them to keep the weapon in operating condition. The gas-operated weapon was very simple in construction and the gunner’s kit reflected the simplicity of the gun.

The kit consists of a simple canvas bag with an adjustable leather shoulder strap. The top flap is secured by a metal roller buckle and leather strap. A single pocket is stitched to the rear inside of the bag to hold the three-piece cleaning rod assembly that also gives the bag form and rigidity. Contents of the bag consist of:

1. Canvas bag with adjustable leather shoulder strap
2. Three-piece cleaning rod assembly
3. Three assorted pin punches
4. Chamber rod
5. Ruptured case extractor
6. Combination tool/wrench
7. Double ended carbon scraper (large)
8. Double ended carbon scraper (small)
9. Spare striker (firing pin)
10. Spare extractor
11. Driving spring
12. Combined solvent and oil bottle. (The “W” is actually the Cyrillic “ShCh” and the word transliterates to “shchelo,” which means lye or alkaline solution/solvent. The “H” is the Cyrillic “N” that transliterates to “neft” or oil.)

By Robert G. Segel

The rare and seldom encountered tool and spare parts wallet is made of brown cowhide leather that folds in half and is secured by a single leather strap attached by a nickeled steel buckle. The wallet is carried in a canvas waist pouch that attaches to a waist belt.

The contents of the tool and spare parts wallet are as follows:

1) Brown cowhide leather wallet with stitched in loops and tool holders.

2) White metal cartridge case remover with claw end.

3) Punches (2), one 0.077 in. (2 mm) and one 0.188 in. (4.5 mm).

4) Ruptured case extractor tool.

5) Unidentified tool (not in manual).

6) Standard folding type screwdriver.

7) Gas regulator adjustment tool. One end is to remove, install and adjust the gas cylinder. The other end is to extract a broken firing pin.

8) Scraper attached to end of cleaning rod segment.

9) Cleaning bore rods (2).

10) Operating spring. 16 3/4 in. long x .38 in.

11) Brass drift or cheater bar.

12) Brass hammer with 2 oz. head with wood handle.

13) Spare parts can (tinned steel). The can is 6 in. long (15.24 cm) and 1 in. (25.4 mm) wide. Note that the can is made up of two sections indicated by a raised rib that can be seen on the outer tube with a steel disk in the interior at the point of the rib that provides a partition. The left hand side of the container as shown here is 4 3/4 in. long (12.065 cm) and the right hand side is 1 1/4 in. long (3.175 cm). The following list of items numbered 16-18 fit in the long left hand side of the tube and items numbered 19-28 fit in the smaller right hand side of the tube.

14) Screw cap for left side of spare parts can.

15) Screw cap for right side of spare parts can.

16) Firing pins (2).

17) Extractor springs (3).

18) Bolt spring.

19) Extractors (3).

20) Threaded brass tube for attaching to bore rods to attach cleaning jag. It is 1 in. (26 mm) long and 0.23 in. (6 mm) in diameter with different internal threads on each end: 0.12 in. (3.2 mm) one side, 0.144 in. (3.6 mm) on opposite end.

21) Feed rack plunger.

22) Feed housing follower stop.

23) Coil spring 29 x 9.5 mm (trigger sear spring)

24) Coil Spring 14 x 7.5 mm (back plate buffer spring)

25) Coil Spring 8 x 3 mm (gas regulator adjustment spring)

26) Coil Spring 15 x 4.4 mm (feed rack plunger spring)

27) Coil Spring 20 x 4.3 mm (undetermined)

28) Coil Spring 28 x 4.4mm (oil reservoir applicator spring)

Japanese Type 99 leather spare parts and tool wallet with all pieces in place.

By Robert G. Segel

Carried by Japanese machine gunners for basic field maintenance, the Type 99 light machine gun (1939) kit consists of a brown cowhide leather wallet with compartments to hold tools and spare parts. The wallet is constructed of two pieces stitched together and folds in on itself and is secured and held closed by a steel buckle that a three-hole strap affixes. Roughly 8 inches long and 3 inches wide, when all tools and parts are in place, the wallet is roughly 2.5 inches thick.

The leather maintenance kit is carried in a heavy tan canvass pouch that is worn on a belt. The rear has a brown cowhide leather rear panel and belt carry loop. The wallet is secured inside the wallet with a brown leather single hole strap and a galvanized steel buckle.

When opened, the kit on the right side top holder and loop contains four bore rods; one with a scraper end. Only one of the rods will accept a jag or brush. The center double loop holds a brass hammer with a 4-ounce head and a small wrench inscribed on one side “barrel securing nut spanner” in Japanese with an arrow pointing to the larger size wrench and “trigger guard nut spanner” in Japanese with an arrow pointing to the smaller wrench on the reverse side. The right lower holder and loop holds a tweezers and a paper wrapped tapered drift rod and a 2.2mm drill bit.

On the left side of the wallet on top is the holder with strap and brass stud that hold a spare bolt (with extractor, extractor spring and firing pin lock cam installed) wrapped in wax paper and the combination tool. The combination tool has a hook on one end to remove an un-ejected cartridge with the cartridge case base intact or missing and is also a hot gas valve wrench. The other end has a twisted wire extractor removal/install tool. The center loop holds the ruptured case removal tool. The bottom holder contains a tight weave cloth parts bag, roughly 2.25 inches by 3.5 inches with a pull string top closure. Contained in the bag are 5 extractors, 2 firing pins, two firing pin lock cams, a wire holder containing 4 extractor spring guides, and 2 ejector door springs and another wire holder containing 7 extractor springs and 2 operating rod stop springs.

By Paul Evancoe

The explosive bonding process has been understood for most of the last century being first observed as a result of warfare. Metal fragments from exploded artillery shells and bombs were observed to bond with other metal objects in the close proximity of the explosion. While the root cause of this phenomena was understood, it’s metallurgical and commercial value was not explored until high explosives were perfected and mass produced during World War II making the explosive bonding process reliable and cost effective. Even then, it was only patented and further developed during the 1960s.

The process involves using high explosives to accelerate two metal plates together at a velocity sufficiently high enough (millions of pounds of pressure) to achieve metallurgical bonding at the atomic level. As sophisticated as this might seem it really isn’t rocket science. Two metal plates to be combined must have clean flat surfaces where they are to be joined. The plates are laid flat in direct contact with one another on an anvil and high explosives are placed on top, evenly covering the plates. Any high explosive will work, e.g., C-4, TNT, Detasheet, even ammonium nitrate if boosted. The explosives are detonated creating the bonded metal plate. The resulting transition joint (weld) is ultra-high vacuum tight giving it high mechanical strength.

This means metals as dissimilar as 6061 aluminum and 304 stainless steel can be metallurgically joined creating bi-metal billets from which the stainless steel is utilized for wear surfaces and the lighter more malleable aluminum for other non-wear surfaces. This makes it ideal for firearms construction because it can withstand drastic thermal and pressure excursions without separation.

The advantage of using explosively bonded metal in firearms construction is because it achieves significant weight savings without sacrificing the resilience and performance characteristics of steel. Neither is there the need for exotic and expensive machining processes used for metals like titanium. Therefore, explosively bonded metal can be machined without the expensive process of special handling or retooling.

The U.S. Army acts as the soldier weapons executive agent for all branches of the U.S. Armed Forces and heads the Program Executive Office – Soldier (PEO Soldier). The number one goal for all future soldier-carried equipment is to reduce the soldier’s load. In other words, make everything lighter and easier to carry. Weight reduction in pistols, assault rifles and machine guns is a worthy goal. However, light construction most always results in reduced reliability and weapon life span. Lightweight weapons made from lightweight materials simply wear out faster than heavier weapons made from heavier materials, especially when continuously exposed to rigorous combat extremes. In short, mass matters. Guns made from explosively bonded metal appear to provide a solution. We decided to find out by operationally testing two explosively bonded prototype model 1911 .45 ACP pistols manufactured by UA Arms.

The size of the explosively bonded billets necessary to build a 1911 frame is 7x5x1inches. Approximately 3/8 of an inch of 304 stainless is bonded to a 6061 aluminum slab. When machined, the stainless is used for the wear surfaces. A rough order of magnitude cost comparison of explosively bonded billets compared to conventional steel and exotic titanium are as follows: The average cost to build a conventional 1911 cast steel frame is about $150 dollars. The average cost to build a frame from a forged steel billet is around $200 dollars. The average cost to build a frame from an explosively bonded billet is $350 dollars. The cost to build a titanium frame is around $475 dollars. Compared to a steel frame, the weight saving in the explosively bonded frame is quite remarkable depending on materials used and model. Conventional all steel 1911’s average 44-46 ounces. UA guns with explosively bonded frames and slides average between 25 and 28 ounces, depending on the model.

The Operational Test Plan (OTP) was designed to test the viability of using explosively bonded dissimilar metals in firearm construction. In this case, 6061 aluminum was explosively bonded to 304 stainless steel. The advantage of using this process is firearm weight reduction without sacrificing reliability, maintainability and availability. Reliability refers to the proper functioning of the gun. Maintainability refers to how easily the gun is maintained and how often maintenance is necessary both routine and repair. Availability is a factor of reliability (failure rate) and maintainability (parts availability, interchangeability, how quickly can it be repaired and back in service) between malfunctions and breakage. Simply, availability means that the gun is in an available status when you need to use it and not broken, malfunctioning or down for repair.

The 1911 .45 ACP was selected because its performance is so well (understood) known and documented over the last 100 years. UA Arms machined ten 1911 frames with integral rails from explosively bonded billets produced by Pacific Aerospace & Electronics (PA&E). UA Arms has exclusive distribution rights from PA&E to use its explosively bonded billets in firearms construction.

Two of these ten pistols, serial #004 and #008, were randomly selected for operational testing. UA Arms custom built these pistols for close quarter battle (CQB). Both guns were ceramic coated inside and out to reduce bi-metal electrolysis and corrosion when immersed in a saltwater environment and to provide a self-lubricious coating to meet the Navy SEAL and Marine Corps special operations requirement to reliably fire a minimum of 200 rounds immediately upon exiting from prolonged water submersion without lubrication.

While testing was not focused upon match-grade accuracy, Uselton installed front blade Novak combat front night sights and Novak rear adjustable combat sights on both guns at the Operational Test Director’s (OTD) request. Novak sights were chosen because they are literally bomb proof tried, tested and proven and there was no need to test the sights, just the guns. Five 8-round blackened stainless magazines by Act-Mags were provided with each gun from UA Arms. Ten additional Novak 8-round blackened stainless magazines nearly identical to the Act-Mags were provided by the OTD.

The Operational Test Plan was designed to operationally test the two weapons using scenarios that realistically represent combat conditions and environments. Only 230 grain ball ammunition was used in the testing, which was derived from a variety of manufacturers that included Winchester, Wolf, PMC and Remington. Ammunition brand was not considered in the testing and was utilized without preference. Gun magazines were mixed among the two guns and not dedicated to a specific pistol.

Prior to turning the guns over to the Operational Test Director (OTD), UA Arms conducted a technical test with Serials #1004 and #1008 under fall-season outdoor dry range conditions. Each gun was fired 300 rounds by UA Arms on their factory range with no reported malfunctions prior to sending them to the OTD. The guns were cleaned, lubricated and shipped to the OTD in like new condition. Please note that rounds fired outside the control of the OTD and this OPEVAL (Operational Evaluation) are not factored into the evaluation data. They are only mentioned for the purpose of gun legacy.

Operational Test Plan

An Operational Test Plan was developed by the Operational Test Director. It was never shared or discussed with UA Arms or anyone else. The OTP consisted of 6 phases of testing. It was designed so that the phases would not need to be conducted in a particular linear sequence. Each pistol was equally tested to the same limits and fired the same number of rounds.

Of note during the testing, all gun maintenance and cleaning was done under field conditions. Lubricants used were WD-40 and CRC Industrial 3-36. All reference to tactical shooting means the guns were always fired outdoors at steel and/or paper pie plates at various ranges for center of mass hits. The guns were never fired on a controlled distance range, either indoors or outdoors, aiming at bull’s-eye scored targets. The following describes each phase of testing.

Phase 1: Tropical Environment 100 Rounds

The Operational Test Director began the test regimen with experienced SWAT team officers shooting on an outdoor tactical range. The guns were fired holding them in the vertical up, down, side and level positions. Because of the 1911’s design, shooting it vertically (up and down) in itself can many times cause feed malfunctions and the OTD suspected that there could be an issue since the pistols were approximately 34% lighter than a traditional all steel 1911.

Within the first 96 rounds fired through Serial #1008 there were five feed malfunctions. The round was getting jammed between the frame’s feed ramp and the barrel feed ramp. There appeared to be an excessive gap between the two. When releasing the locked-back slide (using the release lever to close the slide after reloading) there were also three slide malfunctions where the slide would not carry the next round fully forward and return in battery. Additionally, the slide did not cycle properly during shooting all of which was attributed to a weak recoil spring. Most attention getting, the all-aluminum grip safety failed to work at all. This was attributed to excessive wear from UA Arms’ previous technical testing.

Within the first 80 rounds fired through Serial #1004 there were eight failure to properly feed malfunctions. Like serial #1008, the feed ramp was suspect as was the recoil spring. This gun also had a slide release lever that was too tight to allow easy slide release using one thumb. And, like serial #1008, the grip safety didn’t work for the same reason.

At this point the OTD made the decision to return both guns to UA Arms for the fixes. UA Arms replaced the recoil springs with heavier springs that provided positive slide return/closure. They also polished the lower and upper feed ramps on both guns. To cut weight, Uselton had originally equipped both guns with aluminum grip safety levers that were too soft to withstand the wear from technical testing. Both grip safety levers were replaced with conventional steel levers and the problem was eliminated. UA Arms again test fired each gun an additional 300 rounds on his own range. The guns were returned to the OTD in 6 days in a like new condition and the OPEVAL was resumed. As these fixes were minor not requiring factory (depot level) maintenance, it is important to note that the OTD could have affected these fixes on his own if he had chosen to do so. Rather, outside of the OTP, he chose to test UA Arms’ factory repair turn around which proved excellent.

Phase 2: Winter Environment 400 Rounds

Both guns were lightly lubricated at 28F ambient then fired 100 rounds each on the OTD’s West Virginia tactical range without experiencing malfunction. The guns were again lubricated (not cleaned) and each loaded (rounds chambered and placed on full cock with thumb safeties engaged). They were laid on a wooden platform and fully exposed to a freezing winter environment that included periodic snow and freezing rain for a period of two weeks. Without cleaning, additional lubrication or warming, each was fired an additional 50 rounds without malfunction.

At this point the guns were cleaned in the field and closely inspected for rust, corrosion and any sign of failure of the aluminum and stainless bond. Neither gun showed any deterioration.

The next part of this phase involved fresh water and mud submersion. Both guns were loaded, hammer back, thumb safety engaged and submerged about a foot deep in a flowing freshwater West Virginia mountain brook, resting flat on a mud/sand bottom. After four hours the guns were retrieved and immediately each fired 200 rounds on a tactical range. Serial #1004 experienced a stovepipe feed malfunction on its 8th round. The jam was immediately cleared, the gun was reloaded and it shot the remaining 192 rounds without failure. Serial #1008 shot flawlessly.

The guns were cleaned in the field and lubricated, then loaded (hammer back and thumb safety engaged) and again submerged about one foot deep in the flowing stream only this time they were pushed down into the mud and covered. After 4 hours the guns were retrieved and quickly rinsed off in the stream by running them back and forth through the flowing water to wash the surface mud off the slide and frame. Both guns were then each fired 50 rounds without malfunction.

Phase 3: Temperate Environment 500 Rounds

The guns were each exposed to a demanding 500-round regimen of tactical range shooting from all positions and attitudes (vertical up and down, horizontal conventional, side and upside down. Both guns along with all their magazines were cleaned in the field and lubricated every 100 rounds. No malfunctions were experienced.

Phase 4: Maritime Environment 200 Rounds

In this phase of testing both guns were each exposed to seawater for 4 hours. The guns were lubricated and placed in a mesh nylon laundry sack that was suspended beneath a pier at a depth of 10 feet. Because of the location available for this test the guns could not be loaded with chambered rounds but loaded magazines were installed. Following the 4 hour exposure the guns were retrieved and fired 200 rounds each without lubrication using the tactical regimen referenced previously. Both guns performed flawlessly.

Following this the guns were both rinsed off with fresh water, cleaned in the field, lubricated and closely inspected for rust, corrosion and any sign of failure of the aluminum and stainless bond. Neither gun showed any deterioration.

Phase 5: Desert Environment 240 Rounds

The Operational Test Director was limited in this test phase because of the physical location and the lack of availability to an actual desert environment. Simulating a desert environment was attempted by open carrying the guns in a nylon mesh sack during lengthy sand dune walks in the Virginia capes. Granted, the sand in some deserts, depending upon their location, more resembles fine powder rather than granular sand. This limitation to testing could not be simulated without actual exposure to that particular desert location. The next best simulation was to expose the guns to blown sand.

Following exposure to windblown sand for 30 minutes, both guns were loaded (round chambered with thumb safety engaged), placed in an oven and heated to 130F for 4 hours. The guns were removed and immediately each fired 80 rounds. This sand-heat-shoot cycle was repeated three times with the guns being cleaned in the field, lubricated and closely inspected for any sign of the aluminum and stainless bond after each 80 round cycle. Serial #1008 experienced a failure to feed malfunction on its 4th shot. The slide didn’t quite return to full battery. After being rapped with the palm of the hand it closed fully and fired flawlessly during the remainder of this test phase. Serial #1004 failed to feed on its 82nd shot and like its sister gun, it didn’t fully return to battery. The unspent round was manually ejected with a snap of the slide and the gun continued to fire flawlessly.

Phase 6: Drop Testing 60 Rounds

Drop testing is usually done at the start of testing. Because these pistols were unique, the OTD made the decision to conduct potential destructive testing last. Both guns were cleaned, lubricated, and loaded (round chambered, thumb safety engaged), then dropped from a height of 6 feet onto a hard concrete pad. For safety, the guns were suspended above by their trigger guards and remotely released. Once on the concrete pad, they were retrieved and each fired 20 rounds. The drop test was then repeated twice again as was the firing cycle. Both guns fired flawlessly.

The guns were cleaned in the field, inspected for drop damage, and any sign of failure of the aluminum and stainless bond. Outside of some minor superficial gun finish bruising, neither gun showed any component damage or bond deterioration.

Conclusions

• Test data reflects that the UA Arms 1911 .45 ACP CQB is a reliable combat pistol.
• Explosively bonded aluminum and stainless construction in this pistol makes it approximately 34% lighter than its steel counterpart while exhibiting superior ruggedness, wear resistance, reliability, maintainability and availability.
• Because of the gun’s lighter weight, it cycles much faster.
• The UA Arms explosively bonded 1911 CQB does not require attentive maintenance and possesses superior aversion to corrosion, rust, and internal part seizure.
• CQB variant’s weight and the feel of its action (form, fit, function) provides quicker sight acquisition when engaging multiple targets.
• Because of its aluminum-stainless construction, it possesses a very low magnetic signature when compared to a conventional 1911.
• Internal parts are completely interchangeable with conventional 1911s and they can be mixed as required.
• Training and use is identical to conventional 1911s.
• By nature of the 1911’s design and operation it generally is not fitted with a sound suppressor as the additional weight on the barrel results in failure to eject and feed depending upon the gun’s vertical up/down attitude when firing. While not part of this test, the Operational Test Director believes the UA Arms explosively bonded 1911 CQB may possess the ability to function reliably with a barrel-mounted sound suppressor perhaps also manufactured from bonded material.
• Based upon the results of this testing, the OTD unconditionally endorses the use of explosively bonded materials in the manufacture of all firearms from pistols to machine guns.

(About the Operational Test Director (OTD): Mr. Evancoe is a retired Navy SEAL. During that time he served as an OTD for the SEAL Weapons System during assignment to the Commander, Operational Test and Evaluation Force. Following retirement from the Navy he served as the Director for Special Operations at the Office of the Coordinator for Counterterrorism at the U.S. Department of State, Director of the Office of Emergency Response at the National Nuclear Security Agency, Vice President for Military Operations at FNH USA, president of Aegis Industries, and Liaison Team Lead for inter-agency explosives technology subject matter experts at DHS Science and Technology Directorate’s Explosives Division. He is also the author of three military action novels; Own the Night, Violent Peace and Poison Promise).

“Quad” and the Korean War

There are not too many SAR readers who do not know about the Quad mount for the .50 caliber Browning M2: the M45 Quad mount. It was a very effective weapon system for ground attack. Of course, it was an effective anti-aircraft weapon, but its role as an AA weapon was somewhat limited during its initial service in WW2. It was not its own fault – because of air dominance of the European theatre by allied air forces, its chance of firing against enemy aircraft was not that great. But against ground targets, especially large numbers of enemy personnel, it showed devastating effect. The Quad .50 could shoot almost 40 rounds per second, and those rounds are not just ordinary .30 caliber rounds but .50 caliber rounds.

Soon after WWII, it again showed its effectiveness but this time in Korea. Again, its chance to shoot a target in the sky was very slim, but it was very busy for shooting targets on the ground with targets being plenty of Chinese and North Korean soldiers and equipment.

During the Korean War, Chinese expeditionary forces used ‘human wave’ tactics to overwhelm UN forces’ defense. To counter this threat the U.S. military extensively used Quad mounts. Fire a few hundred rounds of devastating .50 caliber rounds within a few seconds and this literally threw ‘bullet waves’ to stop ‘human waves.’ So many Chinese were mowed down by many Quads that its nickname “The Meat Chopper” was well earned.

Service in Korean Military

After the Korean War, many Quad mounts were supplied to the ROK military by the U.S. and until the late 1970s they were very important low altitude AA systems in the ROK military. The ROK was a very poor country at that time, and if they had something supplied by the U.S. for free or at a very low price, they used it as extensively as possible, since those usually would be the only thing available for them. Since they received a considerable number of Quad mounts (including many M16A1 MGMC half tracks), they used them extensively and bought no other alternatives for a long time.

From the late 1970s, some of them were replaced by more modern weapon systems such as the VADS (Vulcan Air Defense System). The ROK began to make a license-built version of VADS and soon it became the mainstay of ROK’s air defense’s lowest ceiling.

But that didn’t mean the demise of Quad mounts in ROK service. While major AA outfits received VADS, many Quads were also retained and spread to countless areas for a local defense role.

One reason the ROK military didn’t throw away those old Quads, even during the 1980s and 90s, was the AN-2 Colt aircraft. The AN-2 is a Soviet-built biplane, which can fly very slow and very low; its slow speed and low altitude make it especially hard to be detected by radar, so North Koreans bought considerable numbers of them to infiltrate special forces against the ROK. Since Korea is quite mountainous, there are many routes where AN-2s can fly through. VADS are not cheap systems, so the number of them were not enough. Thus, many Quads were placed on scores of mountains or high grounds to cover those routes. AN-2s are not only slow and low-flying, but also quite vulnerable to small arms fire; it has no armor, and its wings are basically metal frames covered with canvas. Only a few rounds of .50 tracers can light this thing up, and once you can see AN-2s, it’s quite easy to hit them with Quads.

AN-2s were not the only concern. Since North Korea can muster considerable numbers of light infantry at many points, those Quads were also used to cover such threats – not much different from the role which it had done during the Korean War.

Another role was mobile defense. While the ROK army has considerable numbers of self-propelled Vulcans (K263; which is similar to U.S. made M163, but using Korean made K200 chassis instead of M113 APC Chassis), most of them are used with mechanized outfits, so some Quads were mounted on 2.5 ton trucks and used as mobile defense for important places like airfields, until the early 2000s.

The name of the Quads in the Korean army was Seung-Gong Po or Seung-Jeon Po. Seung-Gong Po means ‘a cannon to win against air threat,’ and Seung-Jeon Po means ‘Victorious cannon.’ But it seems both of them were not official nomenclature; officially it usually being called as ‘light cannon.’

Not Retiring, But Downgrading

During the late 1990s to early 2000s, virtually all ROK Quads met their life’s end. While some parts were copied during the 70s and 80s, the military felt no need to buy important parts like motors or other power-related parts for the obsolete Quads. Also, the need for Quads become much less than previous years. The number of VADS or K263s now became considerable, and during 1990s to 2000s they bought large numbers of MANPADS (Man-portable air-defense systems, which means shoulder-fired anti-aircraft missiles like the famous Stinger) from France and Russia. From the late 2000s they even began to produce their own version of MANPADS. With new low-altitude radars to detect AN-2s, there seemed not much reason to place so many Quads on the northern side of ROK. So as an original form, M45 Quad mounts officially retired from ROK military in 2010.

But that doesn’t mean the ROK military, in this case the army, wanted to retire all of them; they still wanted to retain some number of them. Usually, most countries upgrade such old systems once they decided to retain them. The ROK did exactly the opposite. They just downgraded them. They stripped off most of the power related parts and removed most of the armored covers around it; and since there’s no power, the seat was also removed. They added a large handlebar on it and attached a bicycle-brake lookalike firing mechanism. Simply speaking, they changed electronically powered Quad mounts into manually operated Quad mounts in which the operator has to stand up and move it with his own muscle. Even before the official retirement of M45, many numbers of them were converted in that way. Of course, the optical sights originally provided were also removed and simple ring sights are now being used.

It’s a somewhat strange decision since most countries retained the M45 for a long time and usually upgraded them; mostly with 20mm cannons and new power system plus new sights. But the ROK army feel they already have considerable numbers of better weapons (like Vulcans and MANPANDS), and Quads are now being distributed more to rear or unimportant areas. The only two things Quads have to deal with now are AN-2s and enemy special forces (or light infantry). Both threats need no power traverse, since AN-2s are quite slow and infantry is much slower than that. Manually operated quads can still track and shoot them, and firepower is still great whether it’s moved by hand or electric motor. Cost-wise it would be quite economical while not as effective as it used to be.

Training and Live Fire

The pictures for this article were taken during the summer of 2010. The place was southwestern part of ROK, where the North Korean threat would be quite less than those of northern areas.

Actually, especially in this area, most of ROK’s manual Quads are operated by reserve forces.

The ROK military’s reserve system needs a little explanation. Unlike other countries, like the U.S., virtually all active military servicemen automatically become reserve after they finish their active military service. Until 4 years after their service, they become ‘mobilized reserve’ which receive 5 days of training per year and would be drawn into active service when war occurs. After 4 years of mobilized reserve service, they now move into the local reserve, which needs 3 years of service and 36 hours of yearly training. These local reserves are not dispatched to active service even in wartime, but defend their hometown or workplace. Most obsolete firearms are being dispatched to those local reserves: for example, ROK army still retains large numbers of M1/M2 Carbines for them.

The place we visited was a training ground to fire support weapons like machine guns. On that day, some reserve soldiers, managed by the army’s 31st Division, had been doing live fire training with the manual Quads. The soldiers were local defense reserves assigned to ‘workplace reserve.’ They were part of the local reserve that literally defends their workplace during wartime. This could include the steel mill, car factory, machine factories or even nuclear power plants.

Some quads were placed at many such places in case of wartime enemy infiltration. It’s quite hard to expect the Quads will be well-maintained in such places. Maintaining the machine guns mounted on them are probably the best they can expect, so removing all power systems was the answer. With that, nothing would go wrong even with minimal maintenance (or virtually without it).

The guns mounted on them are of course the famous Ma Deuces. While the ROK regular army is using the K6, which is the ROK version of M2HB QCB (Quick Change Barrel), all M2s on Quads are regular M2HBs that were all supplied from U.S. and virtually all of them are WW2 vintage. Of course being Brownings, they need to be checked for headspace and timing during barrel change or maintenance. But virtually all reserve soldiers in that place didn’t know how to do that or even didn’t know what headspace or timing means. While some of them used .50 cals. during their active service, their gun was the K6, which requires no headspace adjustment, so it’s natural for them not knowing about that. They’re from a completely different generation. Such work was done by very experienced NCOs and warrant officers who are in active service and supporting those reserves as armorers. Thanks to them, while eight guns were used on that training day, all guns could fire with relative reliability, though there had been a few jams occurring.

Firing the weapon was easier than it seems. Most expected some very hard labor, and indeed it needed some physical strength, but it didn’t require untold strength to use. Also, because it is operated by two loaders, the shooter can have their help to operate the guns. Feeding is basically done by ordinary 100-round ammo cans. The famous ‘tombstone’ 200-round drum cans were long gone from ROK service, and even those old armorers don’t know about them. And for the live fire exercise here, they didn’t even use such ammo cans since ammo was limited. Only 20 to 28 rounds were fired per shooter, so belts were shortened to 5 to 7 round length and fed by hand.

Overall, it’s somewhat a bizarre weapon, and needless to say it’s far from adequate to modern standards. But since the ROK is still confronting an enemy who’s also far from modern standard, these ‘Victorious Cannons’ will stay in ROK service for the time being.

The Thompson submachine gun has been the subject of many stories since its introduction to the international military and police communities in 1921. There are many collectors of this fine weapon worldwide, some owning many of the different variations, most fortunate to own only one. There are also a lot of enthusiasts who do not own a Thompson, but still collect many of the accessories and paper items. As an accessory or paper collection grows in size, it is usually displayed or defined by a specific era of Thompson history. Of course, the Warner & Swasey era was first, followed by the Colt era and then the Maguire/World War II era. The Kilgore/Willis and Numrich Arms Company era are next, followed by the rebirth of the second Auto-Ordnance Corporation at West Hurley, New York. The current Thompson era is now Kahr Arms, located in Worchester, Massachusetts.

Paper items from the Colt era are very popular collectables and can be quite expensive. There are many items to collect given the Colt era lasted for nearly twenty years. Including advertisements, there is probably no one collection that has an example of every paper item produced during this time period. And the list is ever increasing; newly discovered items and what they represent make all collecting exciting. The subject of this story is a set of military manuals that can belong at the end of the Colt era or the beginning of the World War II era.

It all started on January 25, 1940 when the Royal Swedish army ordered 500 Thompson submachine guns for the Svenska Frivilligkåren SFK or the Swedish Voluntary Corps. The plan was to use the Thompson guns in Finland against the Russian army in what has become known as The Winter War. Delivery was made but the war ended before the guns could be issued. These 500 Thompson were then adopted by the Royal Army of Sweden in 1940 and designated Kulsprutepistol m/40 (submachine gun m/40). All 500 Thompson’s were of Colt manufacture and are the only Thompson submachine guns known to have been used by Sweden. (The full story of the Swedish Thompsons can be found in the May, 2009 issue of Small Arms Review.)

Auto-Ordnance 1940 Handbook

Collectors have known for many years that Auto-Ordnance Corporation (AOC) produced a 1940 Edition Handbook written in Swedish. These handbooks are quite rare and not often encountered. Most enthusiasts have never viewed the inside pages, only a picture of the cover. This handbook is almost non-existent in Sweden; enough so as to raise doubts the handbook was ever provided to the Royal Army of Sweden. Recently, a 1940 Swedish Handbook was found in Sweden bearing the name Erik Ahlberg, a former Swedish Army Officer. Military records reveal Erik Gunnar Ahlberg was born on November 18, 1908, was a book printer by trade, and served with a Swedish Landstormen infantry regiment during World War II. The Landstormen was a second line unit, much like the National Guard in the U.S. Ahlberg later received a reserve officer commission on January 1, 1956 and was promoted to the rank of captain with the Kungl. Södra Skånska Infanteriregementet (Royal Southern Scanian Infantry Regiment) I7. Captain Ahlberg recently passed away and the handbook was found while the family was disposing of his estate. It was actually discarded at first, but luckily someone thought to see if there may be any collector interest with this type of item.

Review of the handbook shows it is only 21 pages in length, less than half the size of the commonly found English 1940 AOC handbook. The literal English translation for the language on the cover is as follows:

UPPLAGA 1940
EDITION 1940
UPPGIFTER
DATA
om
on
THOMPSON
THOMPSON
KULSPRUTEPISTOL
SUBMACHINE GUN
MODELL 1928
MODEL 1928

Please take note of the 270 Broadway (New York) address; there are only a few AOC paper items with this address. The next address for AOC would be in Bridgeport, Connecticut.

The Swedish AOC handbook appears to have been designed and printed very quickly. It is definitely not an exact Swedish translation of the commonly found English 1940 AOC handbook. The Swedish order was placed with AOC on January 25, 1940; the ship carrying the Thompson guns and accessories set sail on February 19, 1940. If the handbooks accompanied the guns and accessories, this left only a short time to design, write, proof, print and deliver the handbooks for shipment. The first indication the handbook was written quickly can be found on the front cover. The phase in the lower right hand corner, “Tryck i U.S.A.”, translates in English to: Print in U.S.A. The correct word or phrase should be Tryckt i U.S.A. – meaning Printed in U.S.A. The use of stock pictures from AOC handbooks and catalogs used prior to 1940 indicate it was most likely printed and distributed before the commonly found English Edition of 1940 Auto-Ordnance handbook was compiled. The schematic of the Thompson gun pictured at the front of the handbook is actually a Model of 1921 A Thompson with a vertical fore grip. This same schematic had been used by AOC since the first handbook was published in 1921. All known Swedish Thompson guns were Models of 1928 A (no compensator) with horizontal fore grips. There is no picture in the Swedish AOC handbook of this Thompson variation.

Pictures used in the English Edition of the 1940 AOC handbook would have been much better suited for the Swedish guns. For example, the schematic used in the 1940 English Handbook was changed to a 1928 model Thompson gun with a horizontal fore grip. It also included several pictures of Thompson guns with horizontal fore grips and no compensators – just like the version purchased by the Swedish government.

More evidence of a rush to complete the Swedish handbook involves the use of stock AOC pictures showcasing the 100-round or “C” drum. One picture is of a Thompson gun described as a Model of 1928 shown with a vertical fore grip and a 100-round drum; the other a display of a Thompson 100-round drum, 50 round drum and 20 round magazines. Again, these were older stock pictures used in prior AOC handbooks. Sweden did not purchase any 100-round drums with their order of 500 Model of 1928 A Thompson submachine guns. And Auto-Ordnance had long before officially discouraged the use of 100-round drums with the Model of 1928 Thompson gun.

The First Swedish Manual

After the Thompson gun was adopted by the Royal Army of Sweden, steps were taken in Sweden to prepare a manual for this American weapon. A stand alone 11 page Swedish manual was initially compiled, printed and distributed in 1941. Documentation at the KRIGSARKIVET or War Archives in Stockholm, Sweden, dated December 3, 1940 revealed the initial production run for this first manual was 2,000 copies. Only a few copies of this manual are known to survive today.

The literal English translation for the language on the cover is as follows:

BESKRIVNING
DESCRIPTION
över
over
11 mm Kulsprutepistol m/40
11 mm submachine gun m/40
[THOMPSON]
THOMPSON
[Beskr Ksppistol m/40]
Description of submachine gun m/40
1941 ÅRS UPPLAGA
1941 EDITION

This Swedish manual did update the AOC schematic to show the horizontal fore grip but interestingly, still used the Model of 1921 Thompson actuator and buffer assembly. It appears the schematic was taken directly from the Swedish AOC handbook referenced above, and slightly modified to feature the horizontal fore grip.

It is not unusual to find where past owners have personalized a military firearm handbook or manual with their name. Such is the case with this Swedish Army manual. A quick review shows the name “Ljtn Thisell” (Ljtn is short for Lieutenant) on the cover. Research revealed there was only one soldier named Thisell in the Swedish military, a Nils Erik Gregor Thisell. He was born on May 8, 1908 and served in the same Swedish Landstormen infantry regiment during World War II as Captain Ahlberg, above. Thisell and Ahlberg are not only connected in history by two very rare Thompson instruction manuals; military records reveal they were both appointed as Landstorm Second Lieutenants during World War II. And both received their reserve commissions with the Royal Southern Scanian Infantry Regiment I7 on the same day – January 1, 1956.

It is not surprising the featured AOC Handbook and Swedish Army manual are connected to two officers who served with a Swedish Landstormen infantry regiment. As Swedish production of the m/37-39 Suomi 9mm submachine gun increased during World War II, the 500 Thompson guns or m/40’s became surplus for the needs of the Swedish military and were re-issued to the Landstormen units.

Written on the front cover of Lieutenant Thisell’s manual is the statement “gäller 1/3 1960” – translation: “valid 1st. March 1960.” This passage indicates the instructions inside the manual, though issued in 1941, were still valid on that day. This begs the (unanswered) question about the Thompson gun or m/40 still being used by the Swedish military in some capacity in 1960. If the Thompson gun was not in use or at least in inventory for available use, why write this statement on the cover of an old army manual?

SOLDATINSTRUKTION FÖR INFANTERIET

In 1941, information on the new submachine gun, Kulsprutepistol m/40, was included in the Swedish Army manual, SOLDATINSTRUKTION FÖR INFANTERIET (Instructions to Soldier – Infantry). Much of the information on the m/40 or Thompson submachine gun, including two of the pictures, came directly from the initial 11 page Swedish Army manual, BESKRIVNING över 11 mm Kulsprutepistol m/40, referenced above. While not common, Swedish SOLDATINSTRUKTION FÖR INFANTERIET manuals can be found in the U.S. and make a great addition to a Thompson paper collection. Just remember that detailed information on the m/40 or Thompson gun is only found in the 1941, 1942 and 1943 Infantry manuals.

The 1941 SOLDATINSTRUKTION FÖR INFANTERIET manual was the first to include information on the Kulsprutepistol m/40. As the pictures of the manual covers show, there are three different variations of the 1941 manual: the initial or first edition, a second edition and a later third edition. The information on the Thompson or m/40 in all three 1941 editions is identical.

A new SOLDATINSTRUKTION FÖR INFANTERIET was issued in 1942 that contained information on the Kpist m/40. There were two editions in 1942. Interestingly, the cover marking on the 1942 second edition is different than the 1941 second edition. Instead of using the word ANDRA (Swedish for second), a Roman Numeral II is used. The information on the Thompson or Kpist m/40 in both 1942 editions is identical.

A new SOLDATINSTRUKTION FÖR INFANTERIET was issued in 1943. Only one edition is known to exist. The information on the Thompson or Kpist m/40 in the 1943 manual is identical to the 1942 manuals.

The information in the 1941 and 1942/1943 manuals is not exactly the same, but the minor variations are mostly linguistic. For example, in the 1941 manuals accessories are referenced as follows: “Tillbehör äro: reservdelsask med innehåll rem, gördel med väskor för reservdelsask, 4 stavmagasin och 1 trummagasin.” This translates to: Accessories are: spare parts box with contents, sling, belt with pouches for spare parts box, 4 stick mags and 1 drum mag.

In 1942 the wording was changed to: “Tillbehör äro: ask för reservdelar med innehåll, kulsprutepistolrem m/40, livrem med väska för 20-skottsmagasin och väska för 50-skottsmagasin, 4 st 20-skottsmagasin och 1 st 50-skottsmagasin.” This translates to: Accessories are: box for spare parts with contents, submachine gun sling m/40, belt with pouch for 20-rd mags and pouch for 50-rd mag, 4 pcs 20-rd mags and 1 pc 50-rd mag. While the language is not identical, there is really no substantive difference between any of the manuals – but collectors want every version.

The last SOLDATINSTRUKTION FÖR INFANTERIET manual was issued in 1944. It references the Kpist m/40 as one of three submachine guns in the Swedish Army, but states: “Not described here.” The same notation is used in this manual on many other weapons in Swedish army inventory that were procured in small numbers during World War II.

The picture of the Kpist m/40 in Thompson Model of 1928 A configuration from the infantry manuals is representative of all known Swedish Thompson submachine guns. While an original Model of 1928 Thompson without a compensator is not frequently seen in the United States, the 500 Colt Thompson’s shipped to Sweden indicate that this was indeed a variation that could be easily purchased from the Auto-Ordnance Corporation.

Epilogue

There is one more Swedish publication that contains a reference to the Kulsprutepistol m/40. The reference is only a picture, but the description showcases the international reputation of the Thompson gun, even during the middle of World War II. The publication is the MILITÄRKALENDERN 1943 or Military Calendar. One word in the caption on page 35 tells the world exactly what the Swedish military thought of this American submachine gun: “s. k. gangsterpistol” – translation: so called gangster gun. And who in this country would dispute that!

(The author wishes to acknowledge the great assistance provided to this story by Mr. Peter Soneson, an advanced collector and dealer of Swedish military armaments, Tingsryd, Sweden and Ms. Ann Gillberg, Librarian, Krigsarkivet, Stockholm, Sweden)

In 1943, Russell S. Robinson started the design and development of what many would consider to be a proper machine pistol, i.e. a pistol that would fire automatically yet having recoil so low as to be controllable in this mode of fire. The Model 11 is not a true Constant Reaction gun in which the barrel, extension and bolt are used to pre-absorb recoil, but uses the slide or jacket to provide all of the inertia. This is a unique approach to solving the problems of firing in full automatic with a weapon the size of a Colt M1911A1.

The Model 11 employs two distinct principles: firstly to smooth out the rearward recoil kick and secondly, to smooth out the torque impact resulting from spinning the projectile to about 1,500 rpm which disturbs aim in a light hand held weapon. The second principle involves rotating the barrel while the slide is moving forward, with the rotation of the barrel in the same direction as the spinning projectile. While we will examine in detail the operation and design of the Model 11 later on, we will first take a look into the history of its development, and what role Russ Robinson had in mind for the Model 11 when designing and developing it. It turns out that this was the role of a Personal Defense Weapon (PDW) long before the concept of a PDW came into vogue.

Inspiration from the Gatenby .45

In 1942, an Australian named Gatenby submitted to the Australian Army Inventions Directorate (A.I.D.) for evaluation a very unusual .45 caliber Machine Carbine/Pistol. Intrigued, the A.I.D. sought a version in 9mm for evaluation and Robinson, at the time involved in firing-range tests of his Model 5 Cal. .50 machine gun, was contracted by the A.I.D. to design a version in 9mm.

The Gatenby gun fed rearward out of the magazine, with a fixed buttress on the pistol grip having a fixed firing pin. A sliding barrel was used with about 1.5 inches of movement. When a round was chambered and fired, the force of engraving and friction of the bullet in the rifling carried the barrel forward against a stiff spring, with a spring-biased extractor in the buttress holding the fired case against the breech face. A fixed ejector spun the empty case off the breech face after the barrel had moved forward about 1.25 inches. Hitting a forward stop at its forward limit of movement, the barrel returned rearward, with a fixed finger under the barrel striking the point of the next cartridge in the magazine. This thrust the cartridge rearward against a ramp that guided it upwards, and, simultaneously, the recoiling barrel pushed the point of the cartridge upward and chambered.

Problems with feeding reliably due to insufficient support of the cartridge while the barrel moved rearward, as well as the heavy recoil, made the Gatenby very difficult to control in a full-auto burst mode. The heavy recoil was due to a combination of the simultaneous recoil shock of ignition and the shock of the returning barrel hitting the fixed breech face.

Robinson designed two variants of the 9mm Gatenby, these being known as the Models 8 and 10. While the Gatenby did not continue any further, it did impress Robinson with some aspects of the design. He initially considered that the Constant Reaction principle was only applicable to .30 caliber and larger, but the Gatenby concept inspired him to apply a variation of the principle to a light weight gun. He felt that a cyclic rate of 600 rpm, with continuous recoil of 5.2 pounds, with the recoil varying about 1.75 pounds, would result in an accurate one-hand held machine pistol. The end result was the S.R. Model 11 9mm Machine Pistol.

Development and design of the Model 11

Conceived in early 1943, the drawings were finally completed by March 1944, and construction was approved in November 1944. Major modifications to the design were necessary due to Russ Robinson’s failure to realize that when the slide struck the barrel via the chambered case, substantial energy was lost in getting the six ounce barrel up to slide speed. As a result of this failure, six ounces had to be added to the slide weight at the rear to compensate. These modifications and redesign were finished by mid February 1945. By early September 1945, major components had been fabricated at the Small Arms Factory (SAF), Lithgow and the prototype gun had fired some 1600 rounds in tests.

The S.R. Model 11 9mm Machine Pistol was designed to initially meet some 13 specifications laid down in 1943 following the advice and assistance of Major J.E.M. Hall, then chief of the Army Small Arms Branch, Directorate of Artillery. One requirement that could not be met was the weight, as the slide alone had to weigh one pound. Additional recommendations and suggestions were made by Australian Army and R.A.A.F. service personnel returning from fighting overseas and later by the Canadians. In this revised list of specifications, numbering 24 in total, the weight was increased.

While some of the 24 specifications laid down have been examined in an article from the now defunct Fighting Firearms, (Summer 1996, Constant Reaction Guns II), let us look again at some of the more interesting. These are as follows:

1. Cyclic Rate of 500-600 rpm;
2. Weight not to exceed 2.5 pounds;
3. Provision for automatic ejection of empty magazine from gun;
4. Safety and fire-selection controls must be conveniently located and designed for immediate operation by right and left trigger finger only;
5. Recoil force to be smoothed out to permit accurate auto or semi-auto fire single handed;
6. Except for pushing home successive magazines, no handling or operational function to require a second hand;
7. The action to be kept in a cocked mode upon termination of burst fire as well as ejection of the magazine; and
8. Magazines to be made as expendable as possible.

Some of these requirements and features had never been seen before such as the automatic ejection of magazines when empty. Alternative feed systems were mentioned in place of the magazine. For example, a flexible feed system was proposed feeding through the pistol grip though nothing came about from this proposal. The auto-ejection of empty magazines, coupled with the retention of the gun in a fully cocked position, allowed for a very short time break in firing estimated to be about 0.5 second. The only movement required to re-commence firing was the pushing home of the new magazine. This feature resulted from advice from Australian soldiers fighting in the jungles of New Guinea.

During a trip to Canada, on the way home from the UK in 1945, Russ Robinson visited Small Arms Ltd. and John Inglis Co., Ltd., the latter being manufacturers of the GP35 Pistol and the BREN. Both of these manufacturers expressed a great deal of interest in the Model 11. Colonel Jolley, the Manager at Small Arms Ltd., suggested that a light holster or combination holster/shoulder stock be developed, similar to that of the Mauser Broomhandle and the FN GP35, to enhance the effective range of the Model 11. However, a simple tubular telescoping stock was eventually designed and manufactured, which was attached to the pistol via a tapped hole in the frame. The holster ended up being made of canvas with a separate slip to accommodate the telescoping stock.

When Russ Robinson returned to the UK in the latter part of 1945, he took with him a number of S.R. Model 11 Machine Pistols complete with tubular stocks and canvas holsters. These guns were then later modified after tests in 1946. While these tests were carried out by the UK Ordnance Board, in another ironic twist, the trial report was signed by Major J.E.M. Hall, the Australian Army officer whose advice led to specifications for a 9mm machine pistol being laid down in Australia and ultimately resulted in the development of the S.R. Model 11. Major Hall had been transferred to the UK to work on various small arms projects, and was in charge of a design team working on the .280 rifle project.

The S.R. Model 11, in its initial form, resembled a normal semi-automatic pistol, with the exception of the grooves machined into the exterior of the long barrel. Conducting further research for this article proved the old adage that “hands-on” research provides new insights into a subject. Up until now, it was commonly believed that only four S.R. Model 11 9mm Machine Pistols, including the prototype, were manufactured at SAF Lithgow, though there were some references in official files to a fifth gun being manufactured for spares only. The fifth gun was recently discovered in an official collection in Australia, and it is in an unmodified condition, unlike the other existing Model 11 guns that were modified in England. With the number 5 marked on the slide, it appears that this gun was assembled at SAF Lithgow, and somehow ended up in this official collection along with a modified Model 11 that is now in another official collection within Australia. This discovery allows us to view for the first time what the original Model 11 looked like prior to being modified in England. The markings on this fifth gun match those shown in the original drawings, and the differences between the unmodified and modified specimens are quite striking. The most obvious difference is the extended tang on the pistol grip while the modified slide is longer, heavier and has different markings.

Trials and Tests in the UK

In 1946, the Model 11 underwent sand and mud tests at Enfield held in conjunction with accuracy tests. Major Hall ran these trials, and the accuracy tests produced some interesting results. The Model 11 was found to be more accurate in full-auto fire than the Sten Mk V and the Polish-designed Machine Carbine Experimental Model (MCEM), which is believed to be the MCEM 2. Both the Sten Mk V and the MCEM 2 were used as controls in both the accuracy and sand/mud tests. The accuracy tests showed that the Model 11 was not as accurate as the two control guns in semi-auto fire. The sand and mud tests showed some problems with the change lever and also clearance between the magazine and the housing had to be increased slightly.

Russ Robinson’s work for the British at the time concentrated more on machine guns so the Model 11 received only spasmodic attention to improve the design. After carrying out their initial tests, the Ordnance Board (OB) felt that if it looked like a pistol, was carried like a pistol in a holster, was used like a pistol, and its weight was like a pistol, then it should shoot like a pistol in semi-auto fire. The OB advised Robinson that the gun should be re-designed so that it would provide accurate semi-auto fire but at the same time maintain the accuracy levels achieved with full-auto fire. This was easier said than done, as it would require a major re-design of the Model 11 to allow semi-auto fire from a front sear position, and a change from a fixed firing pin to a more conventional floating firing pin. Robinson looked at this, and this re-design was known as the Model 16. Unfortunately, the Model 16 was never built, with the exception of some firing fixtures.

In 1948, Robinson experimented with heavy alloy metals to try and increase the weight of the slide without making the gun more bulky. Using an alloy made by General Electric Company known as “Heavy Alloy”, which was 50% heavier than steel, new slides were manufactured which were slightly thicker and longer than the original slides. Modifications to the frame included welding an extension to the tang of the frame. Slides were manufactured and fitted to the Model 11 guns that Robinson had brought with him from Australia, and it was envisaged that further tests would result in a total re-design and lead to further manufacture. These tests never occurred because Russ Robinson moved to the United States, and the British had by then adopted the Patchett submachine gun.

Operation of the Model 11

The S.R. Model 11 is a very simple gun with a total of just 22 parts including checkered wooden grips and screws. It has a floating barrel that is the secret of the low recoil force in the various machine pistols designed by Russ Robinson. The floating barrel enabled the forward momentum of the slide to be fully harnessed to pre-absorb almost half of the recoil. The automatic ejection of the magazine is accomplished by an ejection system that is triggered when the rising magazine follower strikes the magazine retainer when it rises to the top of the magazine. The release of the magazine retainer permits the magazine ejector to thrust the magazine downward and out of the butt. At the same time, a heel on the ejector rises and holds the slide slightly to the rear of the sear position. When a loaded magazine is thrust in place, the magazine ejector is rocked upward by the rear wall of the magazine and its heel is withdrawn allowing the slide to move forward .025 inches to rear (cocked) position, and the gun is ready to fire.

When the trigger is pressed, the slide is accelerated forward by the driving spring, the rear end of which bears rearward against the barrel and holds it against its rear stop. As the slide moves forward, it forces the barrel to rotate at a fairly constant angular speed by the grooves in the slide nut engaging the external grooves on the barrel. By the time the slide reaches forward or firing position, the rotational energy of the barrel is about one half that of the fired bullet. When the fixed firing pin of the slide strikes the primer and ignites the charge, a very slight delay occurs while combustion fully develops. At the speed the slide is moving, it wants to move about .030 inches before the recoil is sufficient to arrest and then reverse the motion of the slide. Because of this delay, the slide is arrested in 9mm weapons not by recoil, but by the slide striking the fixed barrel and frame via the fully chambered cartridge case. The greater part of the forward energy of the slide is dispersed into the frame or pistol grip. In order to make the forward energy or movement of the slide fully available to pre-absorb almost one half of the recoil, the barrel of the Model 11 is allowed to slide forward with the slide.

As the bullet leaves the muzzle it has about twice the rotational energy as that of the rotating barrel, so the barrel rotation is arrested and reversed by the rotating bullet. But as the slide moves rearward, the barrel’s rotation is decelerated so that the decelerating torque is in the same sense as the accelerating torque when the slide is going forward. Thus the heavy torque impulse to spin the bullet is replaced by a continuous very small torque which is applied throughout the entire cycle of fire, and which is too small to affect aim during automatic firing.

Each cycle of fire in the Model 11 is followed by a small cushioned blow of the slide against the rear buffer of the pistol grip, which represents a reserve of energy to provide for elevated firing or firing under foul conditions. The blows against the buffer can be felt, but they are very small compared with usual 9mm recoil. The Model 11 was not a true constant reaction gun but it employed a combination of the constant reaction principle with rotating the barrel in the direction of projectile spin, and recoil was reduced greatly by this unique combination. Robinson found that the rapid firing of the gun produced a succession of reactive torque impacts upon the gun, thus affecting accuracy. There is a tendency for such a firearm to react with non-axial twisting pulses. And if these impacts could be cushioned so that the impact is applied to the gun over a long time, then the effects on accuracy due to imparting bullet spin in a very light weapon can be virtually eliminated. The selector mechanism used with the Model 11 is a simple three-position system. The selector is ambidextrous and can be used with either trigger finger. The full-auto position is when the selector lever is fully up and parallel with the slide. Moving the selector lever downwards about 20 degrees clicks it into semi-auto position; and in the safe position the selector lever is fully down and blocking access to the trigger while internally locking the sear.

Ejection of empty cases is via an ejection port in the top of the slide. With the exception of a magazine change, all operations necessary to use the gun require only one hand, thus meeting a major specification laid down back in Australia. Magazine capacity was 14 rounds for the initial holster friendly magazine, and 30 for the subsequent magazines.

The Model 11 U.S. Patent

In 1970, Russ Robinson applied for a U.S. Patent on the concepts he developed with the original Model 11, with the U.S. Patent Office granting the patent on June 12, 1973. The patent disclosed two different approaches to the original ideas as used in the original Model 11, and the additional approach is worthy of some discussion.

The original approach is disclosed though with some differences from the actual Model 11. Rather than have the recoil spring positioned around the barrel as in the actual Model 11, the patent disclosed having the recoil spring being positioned below the barrel. It is believed that this approach was used in the design of the later Model 16. Another difference disclosed in the patent involved the addition of a ring of a resilient material, such as synthetic rubber, to the forward bearing surface between the slide and the external helical grooves in the barrel. This feature was included specifically for the Model 11 as a “…type of firearm…in which a short dwell time occurs in the movement of the slide after it has completed its counter recoil movement and before it receives its recoil movement…”

The alternate embodiment disclosed in the patent was for a firearm with a rotating barrel and two bearings, one at the front of the barrel and the other at the rear, the rear bearing being positioned in the receiver of the firearm. The design allowed for the barrel to be restrained from longitudinal movement, but allowed for the unobstructed rotation of the barrel within the receiver and within the constraints of the two bearings. The receiver included a saddle at the front of the receiver with a friction clip or clamp as a part of the saddle. The friction clip or clamp utilized a simple tension screw that was threaded into a threaded hole in the saddle.

Tightening the screw increased the clamping action of the friction clip and increased the torque resisting the rotation of the barrel with respect to the receiver. When correctly adjusted, the firing of a shot resulted in the barrel being reactively spun by the projectile to an angular velocity in which its angular momentum, less the losses generated by friction, was equal to but opposite to that imparted by the projectile. This resulted in the clamping torque being applied to the barrel so that the barrel was brought to a rest in a period considerably longer than the period of projectile travel in the barrel. Reduction of the torque level and its application to the receiver resulted in the cushioning of the reactive torque impact on the receiver.

Research into the various guns developed by Russ Robinson has failed to find any particular firearm that utilized this version of the invention, and it is believed that this approach was a theoretical design and concept that was never proven in an actual firearm.

The Model 11/16 as a PDW

Examination of personal and official files has shown that, if the problem of semi-auto fire could have been solved quickly, the British would have seriously considered adopting the Robinson gun for use in a multi-purpose role replacing the pistol and the machine carbine. This is the role that Russ Robinson envisioned right from the start for the Model 11, a role now known as a PDW or Personal Defense Weapon.

Initially, the S.R. Model 11 was designed as a standard holster weapon for officers, NCOs, drivers, jungle artillerymen and such, but the fact that it was so light and able to be used with one hand opened up many possibilities for use by other military personnel. Robinson felt that a 2.5-pound 9mm carbine that is normally carried in a holster would be extremely valuable for street and jungle fighting, and night operations. He envisioned that, combining the use of such a weapon with the standard infantry rifle, there would appear to be little requirement for the orthodox type carbine.

The OB was of the opinion that a combination of the self-loading pistol and the machine carbine would be very interesting, but weight would be a major factor. The weight would have to compare favorably with other self-loading pistols for it to be seriously considered. While the weight factor was easily achieved, it was the semi-auto requirement that was awkward to achieve without a major re-design of the gun.

The Model 16 still kept many of the highly desirable features of the Model 11, including one-handed operation, ejection of empty magazines, selective-fire capability, and most critical, a projected weight of 2 pounds 4 ounces unloaded.

The story of the Model 11 finished when Russ Robinson moved to the US, and no further development of the Model 11 or Model 16 occurred. However the specifications laid down for the Model 11 so many years ago mirror, in many aspects, current requirements and operational roles for a PDW/OPW.

Perhaps we do need to reflect upon what has occurred in the past, take heed, and start to break out of the circle that continues in small arms design. Many of today’s so-called advances in small arms have their roots in the past, when lessons were not heeded. Just imagine what would have happened if the British had adopted the Model 11 or 16. Much time, money and effort would not be expended today trying to create a solution that may already exist. In a conversation with Russ Robinson in 1995, he indicated that he would be glad to undertake the design of an improved Model 16 if a firm requirement arose from a responsible source. Regrettably, following his passing away in late 1998, this will not occur. But, perhaps we may still see such a gun incorporating Russ Robinson’s concepts and ideas.

The author wishes to acknowledge the assistance of the following: Australian Army Engineering Agency (A.A.E.A.), (formerly A.T.E.A., Army Technical & Engineering Agency), Maribyrnong, Victoria, Australia; MOD Pattern Room, Nottingham, United Kingdom; the late Mr. Herb Woodend, and the late Mr. Russell S. Robinson in the preparation of this article. Their assistance is gratefully appreciated.