There have been relatively few attempts to introduce new heavy machine gun cartridges since the end of the Second World War. The main reason for this is that many of the roles formerly carried out by these guns have been taken over by cannon of 20mm or larger calibre, while their remaining tasks can be adequately carried out by the existing rounds. However, that has not stopped several manufacturers from experimenting, usually with new technology which possesses some theoretical advantages. The first two considered here are, however, conventional: the BRG rounds from Fabrique Nationale of Herstal, Belgium.

15×115 FN

Having observed that armoured personnel carriers and other light AFVs were acquiring thicker armour as protection against .50/12.7mm AP rounds, FN decided to develop a more powerful HMG to give NATO an equivalent to the Russian 14.5mm KPV. The gun, designated the BRG-15, was a gasoperated, dual-feed design, and it was first chambered for a cartridge made by necking down the 20×110 Hispano case to create the 15×115. However, this experienced difficulties with barrel wear and inaccuracy, so it was decided to replace the cartridge with a new design; the 15.5x 106.

15.5×106 FN

For the new BRG-15 cartridge it was decided to abandon the conventional jacketed bullet design and replace it with slightly larger-calibre projectiles using a cannonstyle separate driving (rotating) band made of plastic. It was also decided to adopt an entirely new case, this time based on theRussian 14.5×114. This is wider than the Hispano case, so it was possible to shorten it while still retaining the same ballistics, resulting in the 15.5×106. Despite all of this work, the project was shelved in 1991.

Several attempts have been made to simplify ammunition and gun design in the postwar period. These have included various shapes of caseless rounds, and “folded” cartridges with the bullet alongside the propellant. Three of the more practical efforts are described below.

.50 Dardick Tround

This system was developed by David Dardick in the 1950s, and was aimed at simplifying the gun feeding mechanism. The basic idea was to push the cartridges sideways into an open chamber instead of lengthwise into a closed one. Three of these chambers were formed on the outside of a revolving cylinder; at any given moment, one round was being loaded, the second fired and the third ejected. The cylinder was partly surrounded by a fixed sleeve; this left two chambers open for loading and ejection, but supported the round being fired by providing the third side of the chamber.

This would not have worked with a conventional cartridge case, so each round was entirely surrounded by a plastic case with three slightly rounded sides. This not only provided a close fit with the supporting chamber walls, but also added strength to make up for the lack of a solid chamber. The description “triangular round” was shortened to Tround.

Most of the initial effort was in small arms with a few examples being made for commercial sale, but these were not successful and production stopped in the 1960s. However, interest in larger-calibre automatic versions continued, mainly because the short cartridge movements involved in chambering and ejection permit a very smooth action with an extremely high rate of fire. Experiments with a .50 calibre Tround MG continued into the 1990s, but did not result in a production gun.

.50 Hughes Lockless

A different approach to the same problem was tried by Hughes in the 1970s. They also developed a gun with a sideways-loading chamber, although in this case the chamber was fixed while the surrounding sleeve moved. The ammunition was in the form of a flat box, which was slotted into the chamber from the side; the shape led it to be dubbed the “chiclet”. Before firing, the loading and ejection ports were covered by a sliding sleeve to complete the chamber. The next round to be c h a m b e r e d pushed the fired case out of the ejection port. This layout led to a very simple gun mechanism, and ammunition was made in calibres from 5.56mm to 30mm, but again without any production being achieved.

The cartridge is interesting because it is of the “telescoped” type; the propellant is packed around the bullet instead of behind it, leading to a much shorter cartridge. Ignition takes place in two stages. The primer first ignites a small quantity of propellant; just enough to drive the bullet up into the bore and thereby seal the chamber. The movement of the bullet exposes holes connecting with the main body of the propellant, which then ignites to drive the bullet from the barrel. The expansion space left by the bullet on its initial movement means thatthe propellant can be packed in tightly, allowing the case to be very compact.

.50 ARES TARG

This was another telescoped round, although with a more conventional cylindrical shape and designed for a very different type of gun action. The TARG (Telescoped Automatic Revolver Gun) was of the conventional single-barrel revolving cylinder type, as the name suggests. The cylinder had four chambers and, as with the Hughes Lockless, ejection occurred when the next round to be chambered pushed the fired case out of the chamber. The project commenced in 1989 and resulted in a light and compact machine gun, but it was cancelled in the late 1990s when ARES was acquired by the AAI Corporation.

In HMGs, as with small arms, much work on producing designs to use advanced ammunition concepts has failed to result in any production contracts. However, it seems unlikely that this will always be the case. The US Army is experimenting once more with telescoped ammunition (both plastic cased and caseless) in the Lightweight Small Arms Technologies (LSAT) programme, while the British and French are bidding to introduce 40mm cased telescoped ammunition in the CTWS (Cased Telescoped Weapon System) for future use in light armoured fighting vehicles. We have not yet reached the end of the development of the heavy machine gun cartridge.

By Robert Bruce

“Though the .50 caliber figures little in the hilltop fighting, it has paid its way in Korea, particularly in defense against infiltration of ground rearward of the infantry main line. Close defense of the artillery gun positions could hardly hold together without this weapon.” Operations Research Office Report R-13, Oct 1951

First introduced into the US military inventory in the 1920’s, John M. Browning’s .50 caliber M2 Heavy Barrel machine gun is still the best in its class. Indeed, “Ma Deuce,” as she has been affectionately called by GI’s for more than seventy years, is still on active duty today. During the Korean War, the powerful M2 HB proved versatile and lethal not only as a single weapon, but particularly so in multiple mounts.

Bigger is Better

While the .30 caliber Brownings were relatively light, portable and effective in combat when properly maintained and utilized in tactically sound roles, their range and hitting power were often inadequate. Faced with well dug in enemy defenses at ranges in excess of 800 to 1000 yards, the rifle cartridges fired by these smaller machine guns fell short in reach and penetration. Fortunately, an excellent solution to the problem was readily available.

The .50 caliber M2 HB can be considered a beefed up version of the Browning M1917 and 1919 guns, sharing many of their mechanical characteristics and combat proven as a star performer in WWII. Although setting of its headspace and timing could be a bit tricky to the uninitiated, the big beautiful Browning earned a reputation for reliability and lethality in ground, air and seaborne operations under the worst conditions.

Plenty of M2s were on hand with Army and Marine units at the outbreak of the Korean War. Of course, each infantry battalion had tripod mounted “Fifties”in headquarters and heavy weapons sections, and this was also the case in artillery, engineer and other combat or combat support formations. These heavy machine guns were a mainstay of perimeter defense as well as giving significant protection against low flying enemy aircraft.

“With the .50 which I was operating, and with an LMG (light machine gun) which PFC Lloyd A. Perry was firing from right next to me, we put up the covering fire which enabled the (artillery) battery to hit the road. As the position was laid out, the guns had to come from my left and turn around the .50 to get on the road…they were a pretty well exposed target. But the .50 and the LMG, together spraying the area ahead of us, kept the enemy fire pretty well dampered.” Sgt. William F. Aragon, 8th Field Artillery Battalion, quoted in ORO-R-13.

Ammunition Options

The exceptional performance of the M2 HB’s ammunition, impressively measuring some 5.45 inches long and weighing a hefty 1800 grains or more, deserves comment. Even ordinary ball cartridges, also designated M2, have a muzzle velocity of about 2930 feet per second and range in excess of 7000 meters. Penetration of the 709 grain gilding metal covered lead-antimony slug at all ranges is also a dramatic leap beyond that of .30 caliber bullets. At 600 meters, for example, the M2 ball would chew through a foot of dry sand and more than two feet of clay, ruining the day for North Korean and ChiCom soldiers even when they are hunkered down in bunkers.

Other types of ammunition are available for special situations such as dealing with lightly armored vehicles. The M2AP cartridge, with its manganese-molybdenum steel penetrator, will punch through a half inch of face hardened steel plate at 600 meters. Then, combined with an incendiary element to light up what’s behind that armor, the M8 API round can be particularly nasty at any range. Tracer fillers to assist fire control are also available in various combinations. The most common at the time was the Tracer, M1, which lights up at about 250 yards and continues to burn out to some 1700 yards.

.50 Caliber Sniping

Although Korea’s abundance of seemingly endless parallel ridgelines was a limiting factor in “by the book” tactical employment of many infantry and support weapons, this terrain feature also prompted a revival in the science and art of long range marksmanship. It is readily understandable why, when the enemy is dug into or advancing along a hillside right across from your position with only air in between, GIs would experience the natural desire to “reach out and touch him.” This was done at moderate ranges with accurized and scoped versions of the ’03 and M1 rifles, but something more was needed when the distance got well 600 or 800 yards.

The 84 pound M2 HB machinegun on its sturdy 44 pound tripod with precision traversing and elevating mechanism is a very stable shooting platform – sort of a self-contained bench rest setup. In addition, its massive “bull barrel” is inherently accurate and 45 inch length helps develop maximum velocity for the bullet. Luckily, performance of the M2 .50 caliber ball cartridge was pretty good despite being mass produced in the tens of millions. Army specs called for “…average of the mean radii of all targets at time of acceptance at 600 yards is not greater than 9 inches.”

Then, since the gun fires from a locked breech and can be operated in single shot mode, it compares favorably with bolt action rifles. “Ma Deuce’s” conversion from workhorse machine gun to sniper weapon is completed with addition of a telescopic sight, and she found gainful employment in numerous observation posts all along the battlefront.

Quad Fifties

M2HBs were also found on tank turrets, truck ring mounts and on other vehicles; notably the halftrack-mounted “Quad Fifty.” Fielded in WWII for both antiaircraft and ground support roles, the Multiple Gun Motor Carriage M16 had four heavy Brownings in a power operated M45 Maxson Mount piggyback on an M3 halftrack.

“…it is an adjunct of infantry fighting that the AA (anti-aircraft) gun has had its most decisive impact upon Eighth Army operations. This is particularly true of the quad-50 (M16). Which has a greater tactical flexibility in ground fighting and a visibly greater demoralizing effect upon the enemy infantry line than the Bofors twin-40. It would be difficult to exaggerate the effectiveness of the quad-50 when used in this role.” ORO-R-13

The M16 system was a good combination of mobility and firepower, able to travel quickly to places it was needed and immediately relocate within an operational area in response to the direction and intensity of enemy actions. The total rate of fire for all four M2s in this system is an awesome 2000 rounds per minute with an effective range approaching 2000 yards. Enemy MIG fighter jets knew better than to make close strafing attacks where Quad Fifties were on the job.

This combo served particularly well in supporting infantry attacks by saturating enemy defensive positions with a hail of steel, severely limiting their ability to resist. In defense of American positions against Communist assaults, a Quad Fifty could drive to the best location needed to repel the spearhead of an enemy assault. Armored sides on the halftrack and a protective shield on the gunner’s station were impervious to rifle caliber small arms fire.

Primary References

FM23-65 and TM 9-1005-213-10 Brig. Gen. S.L.A. Marshall, “Commentary on Infantry Operations and Weapons Usage in Korea; Winter of 1950-51,” Johns Hopkins University, Operations Research Office Report ORO-R-13, Oct 27, 1951
Terry Gander, “The Browning M2 Heavy Machine Gun,” PRC Publishing, Ltd., 1999

By Bob Naess

“Floyd Pope and the rest of the squad stayed off the ridgeline, but Firebug walked on top of it. The entire 3rd Battalion was strung out behind us like a long snake slowly moving up the ridgeline. As we neared a right angle turn in the ridge, the Chinese opened up on Firebug with a machine gun at close range but missed. He hit the ground but started sliding backwards to get off the ridgeline. Unfortunately he straddled a tree and they fired at him again. I ran forward to Pope to see if he knew where the Chinese were located. He said they were right in front of us. We both popped up hoping to get a shot at them. Then we charged their emplacement. They were gone when we reached their position. We could hear their wheeled Maxim machine gun bouncing off rocks as they retreated down a brushy draw.” – From “Misfit Squad” by Sergeant Jack Dean; 17th Regiment, the Buffaloes, Korea, 1951

Only a few years from the end of WWII in 1945, the obsolescent water-cooled 1910 Russian Maxim was back in front line action as a mainstay HMG of the Chinese and North Korean Communist forces in their effort to unite Korea under Communist control. The Yalta Conference in 1945 prescribed that, north of the 38th parallel in Korea, the Communist Soviet Union accept the surrender of the Japanese, who had occupied Korea since 1905, and the US accept their surrender south of that demarcation. From 1946 to 1949, more than 10,000 North Koreans undertook military training in Russia, while North Korea obtained large quantities of Russian small arms and equipment.

The former Korean Volunteer Army, which had fought with the Communist Chinese in their civil war from 1945 to 1949, returned to North Korea as trained, war hardened infantry veterans. Well trained and equipped by the Soviet Union, and with unconditional support from the Chinese, North Korea stepped up its guerilla insurgency into South Korea with a major invasion across the 38th parallel in June of 1950. Once again, the 1910 Russian Maxim was dragged into combat by infantry on foot, tugged along on its wheeled Sokolov mount.

At the close of WWII, the Soviet Union was well supplied with 1910 Maxims. Starting in 1905 and continuing through 1945, Russian arsenals, the only producer of the 1910 Maxim, manufactured close to 600,000 of both the 1905 and 1910 patterns, with only very minor changes in the overall design of gun and mount. Although many of these weapons were destroyed or left Russia during and between the World Wars, the majority of serviceable 1910s remained there after WWII, and they were readily provided by the Soviet government to the North Koreans and newly Communist Chinese military. The successor to the 1910, the Goryunov designed, aircooled SG43 HMG, produced and fielded by the Soviet Union during the latter part of WWII, was also available to North Korea, but the mainstay HMG of the North Korean forces was the 1910 Maxim.

The water-cooled 1910 Russian Maxim, or SPM, embodied the characteristics common to Russian small arms; simplicity, ruggedness and ease of maintenance. The principal virtue of these characteristics was the ease with which unskilled soldiers could learn the use and maintenance of the weapon. The initial production of the 1905 Maxim and its successor, the 1910, incorporated the best features of several earlier Maxim HMGs. The most efficient improvements were the simplified ‘S’ shaped charging handle, a simplified lock that could be easily disassembled without special tools and easily headspaced using shims, and a very simple muzzle booster. The ‘S” shaped handle was much sturdier, involved fewer parts and one less spring, which reduced breakage and helped reduce manufacturing time and materials. The lock was robust, of simpler design, and the mainspring of very high quality and strength. Quick disassembly of the simplified lock was facilitated by the use of split pins to hold pivoting parts. A small cup cut into the end of the ‘T’ handle of the backplate retaining crosspin could be used to compress the split pin ends for their removal and quick disassembly of the components. Adding or removing shims in increments of .002” or .003” under a nut at the point of attachment on the crank spigot greatly aided in maintaining headspace tolerances through changes of locks or barrels. The efficiency and reliability of the piston effect on the muzzle of the barrel in the booster was increased by using a barrel with the muzzle flared to 3/4”.

Among the small number of tools and accoutrements provided for maintenance and cleaning was a reamer on a combination headspace/booster wrench to clean combustion reside from the inside of the booster body. The removable orifice in the front of the booster allowed use of orifices of different diameters to vary the rate of fire of the gun through a range of approximately 450 to over 700 rpm. The box receiver was rigidly held to the trunion/ waterjacket by tapered dovetails, as was the backplate/grip assembly, and a heavy riveted bottom plate unified and strengthened the structure. The waterjacket , fabricated from light gauge steel, was fluted to enhance rigidity and increase surface area for heat dissipation, and these were often “tinned” on the interior surface to reduce corrosion. From early 1943 through the end of production in 1945, rapid filling of the waterjacket was achieved by the addition of a 3” diameter port capped and latched with a stamped hinged tractor radiator cap. This adaptation, copied from the Finnish Maxims, allowed the fast injection of snow and ice into the jacket during winter use, a very practical feature in Korea’s severe winter weather. A sled apparatus could be affixed to the wheels in snowy conditions, and anti-freeze mixed with the water in the jacket prevented the guns from freezing up solid. Use of a hose fitted to a port on the waterjacket delivered steam to a condensing can, eliminating the potential signal of the guns location due to the steam plume from boiling water during continuous fire.

The 1910 Maxim, firing the Russian issue 7.62X54R (rimmed) rifle cartridge, used a fabric belt that was identical to that used in the German MG08, with extended fingers every three rounds to align the belt in the feedway. The reliability of fabric belts is compromised when they are wet, or wet and then frozen, and the Korean climate, often foggy and wet in the warm months and alternately wet and severely frozen in the winter, no doubt tested the patience of the gunners. However, although it is speculation, the continuous 200 round steel link belts used in the Goryunov air-cooled SG43 HMG, also widely used in Korea, would function well in the Maxims and may have been used, eliminating the problems with the fabric belts.

The Russians found during the Russo-Japanese War of 1905 that HMGs on high mounts exposed the gunners to enemy fire, but they did not abandon the practical wheeled mounts. The 1905 Maxim was prepared with a low wheeled mount, designed by A. E. Sokolov, that was continued with the 1910 version. The heavy, wide turntable on which the gun cradle rode, combined with the weight of the gun, wheeled mount, and heavy steel shield made an excellent, very sturdy platform for the 1910. The stability of the mount enhanced the long range accuracy of the gun, which was used effectively by the well trained North Korean infantry.

Early in the war, due to the weight of the guns, mounts and ammo and the necessity of moving them long distances and over mountainous terrain by foot, they were used rather sparingly in defensive positions. Often the guns were used at great ranges, over a mile or more from their targets, to aid in concealment. Using the MGs from long distance to rake the forward slopes against advancing US troops, the North Koreans registered their mortars behind the US soldiers who would fall back when they took too many casualties from the long range MG fire, only to discover they were under mortar fire. As the war continued, it developed into a contest of many fixed positions in mountainous areas which were traded back and forth between the combatants. As with the static trench warfare of WWI, the thoroughly dug-in emplacements of 1910s in defensive positions were very effective in retaining ground gained by the North Koreans.

The Korean War was not the last theater of combat in which the 1910 was fielded, as reports of their use in Vietnam attests to their practical value despite their age and the shortcomings of their weight and rather cumbersome mount. There are still many 1910s in the arsenals of countries scattered worldwide which could well be used long into the future.

By Edwin Libby

The standard heavy machine gun employed by Imperial Japanese forces in the Pacific War was the Type 92, commonly called the “Juki” by the combatants of both sides. This weapon derived its name from its Japanese designation Jukikanju, or “heavy machine gun” and, although this weapon was regarded a medium machine gun by U.S. forces because of its infantry rifle caliber, the gun’s 122-pound weight with tripod readily demonstrated the logic of its “heavy” classification. The gun was air-cooled and 61 pounds was accounted for by a very heavy barrel housed in a massive receiver casing with large radiator flanges to draw heat away form the mechanism during firing. A slow rate of fire of 350 to 400 rounds per minute, and a hollow-sounding report at a distance, earned the Juki the derisive name of “woodpecker.”

The design of the Japanese Type 92 originated with the French Model of 1897 Hotchkiss heavy machine gun, several of which were purchased from the Paris-based Hotchkiss Company, and these guns were used with great success against the Russians in the Russo-Japanese War of 1904-1905. In that war the Japanese Army originated the technique of overhead fire in support of their infantry assaults, but they also used their tripod-mounted Hotchkiss guns to deliver direct fire from front line positions. Although this latter tactic proved to be exceedingly costly in Japanese lives, its success signaled the need for mobile firepower to support infantry on the battlefield. It also stimulated the quest for a light machine gun among the nations who recognized this need from their participation or observation in this first great modern war. After building the French Hotckiss MG under license and after modifying this gun to improve its reliability, the Japanese Army adopted a heavy machine gun of indigenous design, designating it the Taisho Type 3 Model of 1914. This gun was a much developed and refined version of the original French gun with a new and original locking system created by the gun’s designer, Kijiro Nambu, a Japanese Army officer who was to become Japan’s premier firearms designer. Several years later Nambu further refined his Type 3 heavy machine gun with greatly improved iron sights, with added optical sights, and with a new and powerful 7.7mm cartridge for which the refined gun was chambered. In 1932 this gun was adopted by the Japanese Army as the Type 92 heavy machine gun, and this gun was the Japanese heavy machine gun most frequently encountered on the battlefields where U.S. troops were engaged.

Ammunition of various types – ball, tracer, and armor-piercing – on 30-round rigid brass or steel feed strips was used in the Type 92 heavy machine gun. The strips offered a marked contrast to the flexible ammunition belts used by U.S. light, medium, and heavy Browning machine guns and captured Japanese Juki positions littered with empty feed strips and spent cartridge cases remain vivid in the memories of many U.S. combat Marines and soldiers. Each feed strip was packaged in a cloth-covered cardboard sleeve which, with its top removed and the strip engaged in the gun’s feedway, was used to guide the strip and to protect the cartridges on it from dirt and debris. To deliver sustained fire, strips were easily hooked together as they were fed into the gun by the assistant gunner; each cartridge was oiled by a brush in the feedway as it was drawn into the gun.

Ball ammunition of 7.7 diameter (.303 in. caliber) used in the Japanese Type 92 heavy machine gun was loaded typically with a bullet of 204 grains, one of the heaviest rifle caliber ball bullets used in World War II, and very heavy in comparison to the 154-grain ball bullet of the .30 caliber M2 cartridge used in U.S. Browning machine guns. This ammunition gave the Japanese Juki an effective range of 1500 yards, and a remarkable maximum range of 4500 yards. Three different types of optical sights of various powers (4-, 5-, and 6-power) enhanced the accuracy and effectiveness of this weapon. Whenever opportunity was presented the Japanese carefully located and concealed their heavy machine guns and the support positions for these guns, established fire lanes and precise target areas, and registered the fire of these weapons. A Juki in a prepared position and manned by a competent crew was a deadly weapon and a formidable obstacle for any attacking troops.