Auto-Ordnance “Bridgeport” Drums

One of the most common drum magazines encountered by Thompson collectors is what is referred to as the “Bridgeport L drum.” However, very few collectors realize that there is more than one style of these venerable drums. The following are my personal observations and is not meant to imply that one variation is rarer or more valuable than another. Rather, simply a statement of fact for collectors to start looking for the differences.

I am also not going to get into differences in markings where a comma or period is or is not visible. Collectors must remember that dies used to mark parts wear out and among the first thing that wears out are the small marks in the roll die. Manufacturers generally don’t worry about replacing a die until you cannot read all of the information. Instead, I will discuss changes of entire die sets and is what I will call a separate production run.

When Russell Maguire purchased the Auto-Ordnance Corporation on March 3, 1939, he owned a debt laden company with little assets but had some very good prospects. At the time, the Type XX Box and L Drum magazines were being produced by Mitchell Stamping Co. (M.S.CO) and probably Wooster Pressed Steel Co. respectfully. Mitchell Stamping was merged into a new company called United Specialties Company and became one of at least two different stamping divisions, with the headquarters for the new company being in Chicago.

With Maguire in control of Auto-Ordnance, the L drum production was also moved to United Specialties. The exact reason is unknown, but having one company supplying all of the magazines may have been the contributing factor. By the time that United Specialties took over the production of the L drum, the drum face plates already had the well defined drain slots and the cover markings with the “WIND TO 9 CLICKS” at the eight o’clock position on the face.

United Specialty used this design for their first L drums. The first design has the wording “WIND TO 9 CLICKS” (using .185 inch high lettering) centered on the drum face at the six o’clock position. The front face plate uses the drain slots and terminology (with slightly different alignment – i.e., a new set of dies) as the last Wooster L drum. A block outlined capital letter “U” is stamped between the front face plate rivets. The back face plate information still has the New York, NY., USA address (again with slightly different alignment than the Wooster), slightly less well defined drain slots and a block capital letter “U” (not an outlined U).

The second in the series of United Specialties L drums is the first of the “Bridgeport” address drums. This transitional drum’s front cover face plate and instructions are the same as the first United Specialties drum. However, the back face plate now has the Auto-Ordnance address as “Bridgeport, Connecticut”. There is also the “U” between the face plate rivets. This drum was probably made about the time that Auto-Ordnance built their factory in Bridgeport, circa 1941.

The third in the series is the L drum that has the instructions “WIND TO 9 OR 11 CLICKS” (using .200 inch high letters) centered on the front face. The front face plate also has the winding instructions changed to “9 or 11 clicks” and no information on the Model of 1921. Actually, the instruction to wind to 11 clicks is for the Model of 1921. The “U” is marked between the rivets on the front. The back face plate information stayed the same.

The fourth version is the first design to have the Auto-Ordnance “Thompson Bullet Logo” located centered at the 6 o’clock position above the “WIND TO 9 OR 11 CLICKS”. The “WIND TO 9 OR 11 CLICKS” (using .180 inch high letters) is a different font style than the third series as another set of dies were made. All other information on the face plates stayed the same.

The fifth and final version is very similar to the fourth and is the hardest version to visually pick up the differences on. This drum has the “Thompson bullet logo” and “WIND TO 9 OR 11 CLICKS” in what appears to be a bolder type font, using .220 inch high lettering. The front and back face plate instructions are the same though the “U” on the back face plate is now an outlined “U”.

Other World War II L Drum Production

The Crosby Co. (183 Pratt St., Buffalo, NY) – Crosby was contracted to produce the L drum by the British government in 1940. Crosby was paid $25,000 for tooling and $420,000 for the production of drums under a Defense Aid contract (DAW 740-ORD-2). By the end of the war, Crosby had produced about 243,000 L drums.

Crosby drums are considered by most collectors to be low in quality, yet if properly maintained they will function as well as any Thompson drum ever produced. It is just that they were never finished as nicely as other maker’s drums. The metal surfaces were never grit blasted and were either Black Oxide coated or painted black.

The Seymour Products Co. – These drums were originally shipped with a silver sticker label with the company name typed on and applied over the stamped markings on the front face. However, these labels were normally removed by the first users. The body is blued with no grit blasted finish applied. Seymour produced about 190,000 L drums during WWII under Lend Lease contracts. The company was awarded the Army- Navy E Award of excellence for its Thompson submachine gun magazine production on 21 August, 1943.

Wooster Pressed Steel Co., Wooster, Mass. – The company began production of L drums during WWII under a British contract in 1940. Prior to this, Wooster had produced L drums directly for Auto-Ordnance in the 1930’s. The British drums were produced under contract DA-W-241-ORD-726, for a total of 50,000 drums. The WPSCO drums are blued or diluted with no grit blast finish.

Charles Fischer Spring Co. – These drums were produced during WWII. However, all were rejected and ordered to be scrapped. Nevertheless, a few examples still exist today.

Robbins .22 Caliber Drum Magazine – One of the rarest of the WWII drum magazines is the drum for the Robbins .22 caliber conversion unit. Designed and built by Charles Robbins of Cincinnati, Ohio prior to the US entering World War II, it was the first successful .22 caliber conversion unit for the Thompson submachine gun. The units were all hand fabricated and sold to police and military. One sale of these units required Mr. Robbins to be recalled from the Philippines, after “MacArther’s return,” to produce the units for the US Secret Service. After the order was complete he was returned to combat.

Prophylactic Brush Co. – The Prophylactic Brush Co. was contracted by the US Army Ordnance Dept. to produce phenolic Bakelite “plastic” reinforced with hemp rope L drums in 1940. The idea was to reduce the need for steel in the production of magazines. However, the drums were a failure as the plastic drums weighed more and were even more fragile than the steel drums.

In late February of 1942, a prototype of the Savage redesigned Thompson Submachine Gun was ready to be submitted to the Ordnance Department for testing and approval. The Savage Corporation had just conducted their own 10,000 round endurance test, which the new weapon successfully passed. The Savage Corporation told Auto-Ordnance that they were submitting the redesigned Thompson “without any claims for compensation, reimbursement, royalty or patent interest”. The new Thompson was sent to Aberdeen Proving Ground for testing and evaluation. The Aberdeen trials of the new Thompson were rather brief and concluded on 21 March 1942. The Aberdeen report stated that “The overall consideration of the mechanical functioning leads to the judgement that the gun as a mechanism is equivalent or superior to the M1928A1”. After a few government recommended alterations to the prototype were made, the new Thompson was recommended for adoption as Submachine Gun, Caliber .45 M1, at an Ordnance Committee meeting held on 24 March 1942. At the same meeting it was recommended that the 1928A1 be reclassified as Limited Standard. On 25 April 1942, the Ordnance Committee approved the recommendation for adoption of the M1 Thompson.

The Stevens Company’s chief designer Nicholas Brewer, and Savage engineer John Pearce were credited with designing the new Thompson. The M1 model had no provisions to use the drum style magazines. It used the same box style magazine as the 1928A1 model. Savage had estimated the cost of producing an M1 model to be $4.36 for material and $6.94 for labor with 175% in overhead. The total cost for Savage to manufacture an M1 would be $23.44. On 24 February 1942, Savage agreed to a contract to manufacture the M1 model for Auto-Ordnance at a cost of $36.37 per unit, providing Savage with a profit of $12.93 per gun. Auto-Ordnance in turn charged the U.S. Government $43.00 for an M1 model. The price varied slightly from contract to contract.

One of the major design differences between the M1 Thompson and the earlier 1928A1 model was that the M1 used a straight blowback design, eliminating the controversial bronze “H” lock. This allowed the receiver to be redesigned for easier manufacture. The bolt assembly was a very simple one-piece block of steel. The inside of the M1 upper receiver simply had a rectangular channel milled into it to accommodate the bolt. The internal felt oiler of the earlier 1928 model was considered unnecessary and thus eliminated in the M1 design. The cocking handle and slot were moved from the top of the receiver to the right side. An enlarged takedown notch was cut in the slot to allow the handle to be easily removed for disassembly (after the receiver has been separated from the frame). Since the drum style magazines had proven unsuitable for military use, the M1 series receivers were not designed to utilize them. The lateral grooves on the sides of the magazine well for accommodating the drum magazine were eliminated.

Like the 1928 and 1928A1, the early M1 Thompson used a separate firing pin and spring, that was the same as the ones used in the earlier models. A separate hammer was also used but the hammers for the M1 were configured differently than that of the 1928 and 1928A1 models. The 1928 series hammers were a triangular configuration, while the M1 hammers were crescent shaped.

Both the recoil spring pilot rod, and the buffer were redesigned for the M1 series Thompson receivers. The pilot rod for the recoil spring was simplified for easier manufacture, and was held in place by the new style buffer. The M1 buffer assembly consisted of a fibre plate secured between two metal plates. The buffer was a substantial improvement over the simple fibre disc used in the 1928 series Thompsons. The M1 pilot rod and buffer also made disassembly and assembly of the weapon much easier, and lessened the possibility of damaging the recoil spring in the process. The pilot rod could be removed and installed through the rear of the receiver once the buffer was removed.

The M1 featured a smooth, unfinned barrel that was similar to the one fitted to the late 1928A1 models, but the muzzle end was not threaded for fitting a compensator. A simple blade style milled sight was fitted and pinned to the muzzle in place of the compensator.

Early M1’s were assembled using the same uncheckered “paddle” style rocker and safety levers that were used on the U.S. 1928A1 model. The magazine latches on many M1 and M1A1 weapons were the same style as the 1928 and 1928A1 type that had a raised area for securing a drum magazine. Since the M1 series would not accommodate a drum style magazine, the magazine latch was later redesigned, and the raised area on the latch was eliminated.

The pistol grip was reconfigured to fit the redesigned M1 trigger frame, and the stock was redesigned as it was now semi-permanently attached directly to the frame with screws. The contour of the stock also differed from the earlier 1928 and 1928A1 design. The stock’s buttplate was also simplified, but retained a spring-loaded trap door for storage of a larger cylindrical oil bottle. The early M1 stock came from the factory without the reinforcing cross bolt installed. The cross bolts were not included until mid 1943 on the M1A1, although most M1 models had their stocks upgraded to include the cross bolt. The standard military horizontal style foregrip was installed on all M1s.

One of the distinctive features of both the M1 and M1A1 guns were their breech bolts, that had been redesigned to have two sear notches machined into them, so that the weapon’s safety could be applied when the bolt was forward on an empty chamber. The 1928 and 1928A1 bolts had only one notch machined into it, and the safety could not be applied when the bolt was closed. Several accidents had been reported with earlier 1928 and 1928A1 models when the weapon was carried with a loaded box style magazine and the bolt closed on an empty chamber. If the weapon was accidentally dropped on its butt, inertia would allow the bolt to travel rearward far enough to pick up a round from the magazine, but often not far enough to engage the sear (that would have held the bolt rearward). The bolt would begin to move forward and chamber the round. The result was usually an accidental discharge of the weapon.

Note; some very early M1 Thompson bolts were manufactured with only one sear notch. An Ordnance Department directive ordered that all one-notch bolts be deemed obsolete, and be replaced with the two-notch bolts as they became available.

While in July of 1942, Savage had turned out 48,000 M1 guns, Auto-Ordnance was struggling to meet its scheduled production mark. The assembly line conversion from the 1928A1 model to the M1 in July through October of 1942, caused serious production setbacks at the Auto-Ordnance plant in Bridgeport. Contributing to the production delays were problems in deliveries of materials, equipment and tooling authorized by the government for M1 production.

After the M1 production finally commenced at the Bridgeport plant, more problems were encountered. The Springfield Ordnance District refused to accept any of the Auto-Ordnance manufactured M1’s because their full-auto cyclic rate exceeded the 860 rounds per minute Ordnance Department specification. Officials from Washington, the District Ordnance office along with Auto-Ordnance engineers conducted studies and tests, all failing to provide a correction for the condition. Finally on 9 December 1942, official notice from the Ordnance Department’s office in Washington gave the district permission to waive the rate of fire requirement and accept the Bridgeport M1 guns. In the interim, identical M1 Thompsons being produced at Savage were being accepted in large quantities by the Rochester Ordnance District without any problems.

The rear sight that was first installed on the M1 was the same simple unprotected “L” style that was also installed on late manufacture 1928A1s. This design proved to have several flaws and was replaced by a similar sight, but with protective side ears added. On 29 June 1942, a letter was sent from Auto-Ordnance to Savage requesting a few changes in a contract originally dated 24 February 1942. One of the changes proposed was to the rear sight. Savage agreed to the changes as long as they conformed to Auto-Ordnance drawings 42-53 for the front sight and A42-86 (protected rear sight). Auto-Ordnance accepted the proposed supplement to the original contract on 17 July 1942. The new sight first appeared on the Savage Arms M1 Thompson in the high 137,000 serial number range. All of the Subsequent M1 and M1A1 models were fitted with new “protected” style sight. The drawing number for the new sight was B147717.

A few of the M1 side-protected style “L” sights have been noted on 1928A1 models depicted in Army manuals. Two such weapons were also documented in the author’s database. The protected rear sight was introduced after the 1928A1 production run had concluded. A protected type of “L” sight fitted to a 1928 model was most likely the result of the weapon going through an Ordnance Department rebuild program.

While Lyman manufactured most of the “L” style sights, Savage, Auto-Ordnance and the H.L. Judd Company manufactured the improved model with side protectors. Manufacturer’s markings noted on the second design sights are either AOC or J, but the majority of them appear to be unmarked. The rebuild guidelines of the Ordnance Department required that all rear sights without protective side ears would be replaced with rear sight drawing number B147717.

There were approximately 285,480 M1s manufactured by Savage Arms and Auto-Ordnance, Bridgeport. Savage Arms manufactured the vast majority of the early M1 model.

This article was excerpted in part from the book “American Thunder, the Military Thompson Submachine guns”. The book is now available from Moose Lake Publishing 207-683-2959

Note; while the “L” sight and smooth barrel began to appear on mid-range serial number Savage 1928’s they appeared on lower numbered Auto-Ordnance, Bridgeport guns. The reason is that the Savage factory began manufacturing the guns approximately eighteen months before Auto-Ordnance. Thus, a low numbered Auto-Ordnance 1928 model was manufactured at the same time period a mid-range number Savage gun.

The Cutts compensator was retained on all military A-O 1928A1 models throughout production. Most of the Auto-Ordnance, Bridgeport Thompsons were fitted with the late (4th) style compensator that has the Thompson bullet logo on the left side, and the Auto-Ordnance name roll marked across the top of the leading edge. All M1928A1 model Thompsons made at the Auto-Ordnance, Bridgeport plant were originally fitted with the horizontal style foregrips.

The Auto-Ordnance, Bridgeport plant was under the jurisdiction of the Springfield Ordnance District in 1941. Thompson Guns were inspected and proofed by on site Springfield ordnance inspectors. The initials of the chief executive officer of the respective Ordnance Districts, who were designated as Army Inspectors of Ordnance or AIOs, were stamped on the guns indicating that they accepted the weapons on behalf of the United States Government. Springfield District Chief executive officers during WWII Thompson production were; Waldemar Broberg and Lt. Colonel Guy H. Drewery. Subordinate ordnance officers managed the inspection process, and all of the guns were actually inspected and stamped by personnel working under their respective chief inspectors. The purpose of the government inspection was to insure that the material being manufactured was the type, quality and quantity specified in the government agreement with the provider. Great emphasis was placed on government contractors to perform their own quality inspections at their factories to avoid having material rejected by the government inspectors. This was done to avoid delays in badly needed materials and to avoid the expense of rejected goods. The quality fit and finish of the Auto-Ordnance produced guns was identical to those of Savage manufacture. Interchangeability of parts was 100% as per Ordnance Department directives.

Model of M1928A1 parts manufactured by Auto-Ordnance’s factories or subcontractors and marked AOC were; Receivers, trigger frames, Blish locks, bolts, actuators, barrels, grip mounts, butt plates, sears, sear levers, trip levers, disconnectors, safety levers and pivot plates.

Although the Remington Arms Company was subcontracted to manufacture many Thompson parts for Auto-Ordnance, in January of 1942, Auto-Ordnance acquired the machinery from Remington and moved it into their Bridgeport plant and began manufacturing the parts themselves. These parts included the actuator, bolt, extractor, ejector and disconnector.

An interesting variation of the Auto-Ordnance, Bridgeport produced M1928A1 Thompson that has been observed, are those Thompsons that have had the U.S. designation ground off and the A1 mark overstamped to read AC. Many of the guns documented had been refurbished, and fitted with the smooth barrels and the “L” style fixed rear sight. Many, but certainly not all, of these guns so altered were in the 150,000 to 152,000 serial number range. A letter X was added as a suffix on the serial numbers of many of these guns. A few other examples of these “1928AC” Thompsons documented were fitted with the finned barrel and Lyman adjustable rear sight. A small number of these Thompsons had their original military horizontal foregrip replaced with the early style vertical foregrip. It is believed that these were guns that had been purchased from the government by the Auto-Ordnance Corporation and refurbished in order to be sold to law enforcement agencies after they were surplused. The Numrich Arms Corporation also removed U.S. markings from 1928 and 1928A1 model Thompsons they sold in the 1950’s.

Interestingly, some of the AO “1928AC” overstamped Thompsons did not have Army Inspector of Ordnance (AIO) acceptance stamps on them, but were stamped with the Ordnance “wheel” acceptance mark. While other examples of these guns had no government inspector or acceptance stamps at all, suggesting that they were never inspected or accepted by the U.S. Government. Perhaps these guns were contract overruns or assembled from parts that remained after the government contracts were filled. However, no documentation could be located that could prove or disprove this theory.

A Treasury Department IRS Form dated June 30, 1944 reveals that two Auto-Ordnance manufacture U.S. 1928A1 Thompsons with an X suffix added to the serial numbers were sold to a Massachusetts police department that year. The U.S. was ground off and the letter C over stamped on the 1 on both of the guns. Please note that the war didn’t end until the 15th of August 1945. All of the 1928 “AC” guns documented were originally manufactured by the Auto-Ordnance Corporation’s Bridgeport factory, and in almost every case had an AO prefixed serial numbered frame, although most of the frame/receiver numbers were mis-matched. The serial numbers located on the frames of these weapons also had the letter X added to them.

Although most of the Bridgeport manufactured Thompsons documented had the very common mismatched receiver and frame numbers, I found it interesting that in almost every case of an Auto-Ordnance, Bridgeport mismatched gun, the frames were also of Auto-Ordnance manufacture. Even though the Savage frames are completely interchangeable, few Auto-Ordnance, Bridgeport guns were observed with Savage trigger frames. The only two serialized parts on wartime Thompsons were the receiver and the trigger frame. The only reason for this was that when the Thompsons were manufactured the lower frames and receivers were hand fitted to each other to insure a close fit between the two parts. It was purely for cosmetic purposes, and had no bearing on the reliability or functioning of the weapon.

As per standard Ordnance Department procedures when there was more than one contractor manufacturing the same weapon, there were separate blocks of serial numbers assigned to each contractor. This was done so that no two weapons would be produced with the same serial number. However, during the military run there were some numbers duplicated, and a few more that were only one or two numbers different, the only difference being the letter S or AO preceding the serial number. Even though there were serial numbers that were close or duplicated on Savage and Auto-Ordnance guns, the dates that those Thompsons had actually been manufactured were quite different. By the time Auto-Ordnance, Bridgeport had produced their very first M1928A1 gun, Savage had shipped well over 200,000 1928 and M1928A1 model Thompsons.

Other major variations of the Auto-Ordnance, Bridgeport manufactured gun were the same as the Savage models.

Finned barrel, Lyman adjustable rear sight.
Finned barrel, “L” style rear aperture sight.
Smooth barrel, “L” type rear sight.

The Auto-Ordnance Corporation manufactured several experimental prototypes of the Thompson in an attempt to get more life out of the original design. There were 1928 model variations chambered for the U.S. 30’06 caliber, as well as a few prototypes made chambered for .30 carbine cartridge. The rifle cartridges proved to be too powerful for the Thompson’s Blish lock delayed blow-back system.

On 25 April 1942, the M1928A1 Thompson was reclassified as “Limited Standard”. The M1928A1 weapons were to be replaced in service by the new M1 version of the Thompson and the M3 submachine gun that was under development by the Ordnance Department and the Guide Lamp Division of General Motors. Due to unforeseen problems the M1928A1 model continued to be manufactured until the autumn of 1942.

Auto-Ordnance, Bridgeport manufactured their last U.S. M1928A1 model on 15 October 1942. Thereafter they concentrated on producing the M1 and M1A1 model. Government documents show that the Bridgeport factory manufactured a total of 323,900 M1928A1 Thompsons. The grand total of 1928 and M1928A1 Thompson Submachine Guns manufactured during WWII, by both Savage and the Auto-Ordnance facilities was an estimated 1,070,832 from 1940 to the fall of 1942 when the M1928A1 model was superseded by the M1 version.

The official end of the M1928A1 model came at an Ordnance Committee meeting held on 16 March 1944 item 23248; Memorandum for the Standards and Specification Section, Conservation Branch, Production Division, Army Service Forces. It was noted for the record that; “U.S. Army specification 52-3-30 of Gun, Submachine, Thompson, Caliber .45 M1928A1 be canceled in accordance with paragraph 30, AR 850-25”. The request was approved.

This article was condensed from relative information in the book AMERICAN THUNDER: The Military Thompson Submachine Gun, available from Moose Lake Publishing LLC. 207-683-2959

Auto-Ordnance, Bridgeport

Although all Thompson Submachine Guns have the Auto-Ordnance Corporation name roll-marked on the receiver’s right side, only a small portion of the total production were actually manufactured at the Auto-Ordnance Corporation’s own Bridgeport factory, especially when compared to the total number made. The Auto-Ordnance Corporation had first relied on Colt’s Patent Firearms Manufacturing Company in 1921, and then Savage Arms in 1940 to actually manufacture the Thompson for them. It wasn’t until the autumn of 1941 that Auto-Ordnance opened its own factory, to assist Savage with the overwhelming wartime demand for the weapon.

Russell Maguire opened his Auto-Ordnance factory in a former automotive brake shoe plant located in Bridgeport, Connecticut. The first months after the building was occupied were spent renovating the facilities, and making tools and gauges not already supplied by Savage. By August of 1941, the plant was manufacturing the U.S. M1928A1 model. At first Auto-Ordnance only made receivers and frames in house. Their guns were assembled with parts purchased from Savage and other subcontractors. The plant ran seven days a week and worked two eleven-hour shifts per day. In January of 1942, Auto-Ordnance began to renovate other buildings on the property to further increase production. The Thompsons being produced in Bridgeport were identical mechanically and in appearance to those being made by Savage. All 1928 Thompsons that were made at the Bridgeport factory had with the letters “A.O.” preceding the weapon’s serial number. The serial numbers, like on the Savage and Colt guns, were roll-marked on the center of the left side of the receiver. A duplicate serial number was stamped on the trigger frames, under the stock slide attachment. The marking of the serial numbers on many Auto-Ordnance, Bridgeport guns was rather carelessly done, as the numbers are quite often unevenly spaced and out of line.

The production of Auto-Ordnance, Bridgeport M1928A1 models began approximately sixteen months after Savage. This would mean that a low serial number Auto-Ordnance, Bridgeport M1928A1 would have been manufactured at the same time period as a mid-range Savage M1928A1, and so on. The receiver markings on Auto-Ordnance, Bridgeport Thompsons differ slightly from those on the Savage guns. All 1928 Thompsons manufactured at the Bridgeport factory were US Model 1928 A1’s. The U.S. designation, like early Savage Thompsons had no periods after the letters.

The receivers of Savage Thompsons were roll-marked on the left side “Model of 1928”, while the receivers manufactured by Auto-Ordnance, Bridgeport were marked “Model 1928” without the word “of “ being included. Another detail difference on the receivers was the abbreviation for the word number, stamped before the weapon’s serial number. On Savage Thompsons the abbreviation “NO.” was used, while Auto-Ordnance, Bridgeport guns used the slightly different “No.” abbreviation. The style (font) of the lettering used on the Savage produced Thompsons was also slightly different than that of the Auto-Ordnance guns.

The Auto-Ordnance, Bridgeport plant was under the jurisdiction of the Springfield Ordnance District. Thompson Guns were inspected and proofed by on site Springfield ordnance inspectors. The Army Inspectors of Ordnance or AIOs of the Springfield District during WWII were Colonel Waldemar Broberg and Lt. Colonel Guy H. Drewery. Colonel Waldemar Broberg using the stamp WB, served as AIO of the Springfield District from 1 July 1941 until 30 June 1942. The stamp bearing his initials has been observed impressed on the receiver’s left side above the magazine well area. GHD was the stamp of Lt. Colonel Guy H. Drewery who replaced Colonel Broberg, serving as AIO from 1 July 1942, until 15 July 1945. His stamp was often placed on the receiver’s left side, just forward of the Thompson Submachine Gun logo. The WB inspector’s stamp would be the most common mark encountered on Auto-Ordnance, Bridgeport manufactured US 1928 A1 Thompsons. Colonel Drewery took the position of AIO near the end of the US 1928 A1 model production run at Auto-Ordnance. His initials are primarily only seen on Auto-Ordnance, Bridgeport manufacture M1 and M1A1 models.

An interesting variation of the Auto-Ordnance, Bridgeport produced US 1928 A1 model that has been observed, are those Thompsons that have had the US designation ground off and the numeral “1” of the A1 mark overstamped with a letter “C” to read AC. A letter X was often added as a suffix on the serial numbers of these guns. Interestingly, some of the AO “1928AC” overstamped Thompsons did not have Army Inspector of Ordnance (AIO) acceptance stamps on them, but were stamped with the Ordnance “crossed cannon” acceptance mark. While other examples of these guns had no government acceptance stamps at all, suggesting that they were never inspected or accepted by the U.S. Government. Perhaps these guns were contract overruns or assembled from parts that remained after the government contracts were filled. However, no documentation could be located that could prove or disprove this theory. The Numrich Arms Corporation also removed U.S. markings from original 1928 and 1928A1 model Thompsons they sold in the 1950’s.

The quality, fit and finish of the Auto-Ordnance produced guns was identical to those of Savage manufacture. Interchangeability of parts was 100% as per Ordnance Department directives.

The West Hurley 1928 Model

The Numrich Arms Company of New York purchased the remaining assets of the Auto-Ordnance Corporation in the 1950’s. They were the third company to do so since 1945. Included in the sale were several complete Thompson submachine guns, and a large number of spare parts. Numrich sold many Thompsons that they had assembled from the parts. Many of these guns have NAC added to the serial numbers. These guns were sold to police departments and a few affluent individuals that could afford the $200.00 transfer tax back in the 1950’s. Approximately ten to twelve guns were sold per year until early 1961 when Numrich ran out of critical receivers and frames and no more Thompsons could be assembled.

In 1975 the Numrich Arms Corporation of West Hurley, New York after receiving approval from the BATF, decided to begin manufacture of both semi-automatic-only and full-automatic versions of the Thompson 1928 model, using the Auto-Ordnance name. The receivers, trigger frames bolts and barrels were of new manufacture, while the remainder of the parts used to assemble the early guns were GI surplus. The parts were Savage manufacture, the original Auto-Ordnance, or one of their subcontractors. As production of the West Hurley guns continued, many parts became unavailable, thus forcing the company to manufacture whatever parts they needed to continue production. In the first year of production there were only 199 select-fire 1928 models made.

In addition to the Thompsons the company also produced a thirty-nine round and a fifty round “L” type drum magazines for the guns. Surplus twenty and thirty round GI magazines were also offered. In 1991 the company began a limited run of the coveted one hundred round “C” drum. There were also special commemorative versions of the 1928 Thompson made. Some of the commemorative West Hurley guns were accepted by the BATF for inclusion on their Curio and Relics firearm list.

Most of the 1928 Thompsons manufactured by the modern Auto-Ordnance Corporation of West Hurley, New York were fitted with a compensator equipped finned barrel, vertical foregrip and a replica of the original Lyman adjustable rear sight. The receivers, frames and barrels of the guns were finished with a black oxide, much like the originals had been. Although the majority of the guns had the aforementioned features, special requests were often honored for specially equipped and serial numbered guns. Special order 1928 guns have been documented with and without compensators, rudimentary military “L” and protected “L” style rear sights, as well as military horizontal foregrips. Wide ranges of custom serial numbers were also issued upon a customer’s request. By the time production ceased in 1986 West Hurley Auto-Ordnance had produced a total of 3,306 select-fire 1928 models. Small production runs of a .22 caliber version of the full-automatic 1928 model were also manufactured.

The West Hurley manufactured Model 1928 receivers were uniquely roll-marked as; U.S. MODEL 1928, with the U.S. mark, but lacking the A1 suffix as stamped on the original military guns. The rear of the receiver’s left side was marked THOMPSON SUBMACHINE GUN CALIBER .45M1. This marking was different than the original markings, and the word caliber was not spelled as calibre as the original 1928’s had been. The center of receiver’s right side was marked AUTO-ORDNANCE CORPORATION WEST HURLEY, NEW YORK, U.S.A. The markings on the trigger frame were reminiscent of those of the WWII Auto-Ordnance guns with the words FULL AUTO on one line. The rocker pivot position arrow was also the smaller design of the original Auto-Ordnance frames.