Garand’s Bullpup

In late 1945 the US Army’s Light Rifle Program began its search for a new rifle weighing less than 7 lbs. The first of these designs was the T-25 developed by Earle Harvey with the backing of Colonel Rene Studler, the chief of the Small Arms Division of the Office of the Chief of Ordnance. In 1946 two other designs began to be developed: the T-28, designed by Cyril A. Moore which used a German-inspired roller locking action and John Garand’s innovative but unorthodox T-31.

Garand was eager to maximise the length of the weapon’s barrel and decided to use a bullpup layout. While not weighing less than 7 lbs the T-31 was the lightest of the Light Rifle program weapons weighing 8.7 lbs. The rifle used a gas trap system, similar to Garand’s earlier designs, to cycle its action. Almost the full length of the barrel was shrouded by a gas cylinder. Once fired the propellant gases of an ignited round were directed down the cylinder to push a short stroke tappet piston which pushed the bolt rearward. 

While there are no diagrams of the rifle’s action available to show how enclosed the cylinder was early prototypes (namely the first and second made) have been described as using a Lewis Gun-like vacuum system where gases leaving the muzzle break were sucked back into the cylinder to the piston both cycling the weapon and helping to cool the barrel. While a later prototype has an entirely enclosed gas cylinder which had a gas port near the muzzle where the cylinder ends and a more conventional piston system. 

The problem with this system is the large amount of surface area the gases have to cool, condense and deposit carbon. This was the issue which doomed the early German semi-automatic rifles the G41(M) & G41(W) as well as the early gas trap M1 Garands. Following a 2,000 round test of the T-31 it was reported by testing officers that almost 1 pound of carbon was scrapped from the internal walls of the gas cylinder. This not only made the rifle heavier over time but would eventually prevent gas reaching the piston causing the rifle to fail to cycle.

The ergonomics of the T-31 prototype appear awkward with a large 20-round box magazine sitting just behind the pistol grip and in front of a large squared off rubberised butt stock. The rifles were 84cm or 33 inches in length and were fitted with adjustable folding sights, designed and patented by Garand but clearly influenced by those of the German FG-42. The in-line stock profile helped to reduce the recoil of the large T65 round.

In response to the problems of carbon fouling discovered in the gas cylinder of the early prototypes Garand developed a longer stroke gas piston system which tapped gas directly from the barrel to reduce fouling and improve reliability.

The rifle was select fire with the large muzzle break on the first two prototype rifles designed to mitigate blast and recoil. The T-31 had a cyclic rate of 600 rpm and fired from a closed bolt which some sources describe as a rotating bolt and was chambered in the ‘Lightweight Rifle Calibre .30′ round (T65) which evolved into 7.62x51mm. The 20-round box magazine was designed by Garand and was the only element of his design which would survive as it was later used in the successful T-44 rifle which became the M14.

Garand continued to work on the design until he retired in April 1953, at the age of 65, the T-31 design was never realised as a practical service rifle and the both Moore and Harvey’s rifles were also eventually abandoned in favour of the T-44. John Garand’s last rifle design was just ambitious and innovative as his early work, the T-31 was not only the lightest of the Light Rifle program’s three early rifles but it also attempted to combat the heavy recoil of the T65 cartridge, which while designed to be an intermediate cartridge was still too powerful. Garand died in February 1974 at the age of 86.

See also: John Garand’s .30 Calibre Carbine

Sources:

If you enjoy the content please consider supporting Historical Firearms through Patreon!

Prototype Cutaway of the Day:  T52E3

The T52E3 was the last in a long line of prototypes built by the US between 1944 and 1957, it would finally be adopted by the US Army in 1957 as the M60 light machine gun.   It's predecessors the T24 and the later T44 had been stepping stones leading to the T52.  It retains the MG42 and FG42s influences with the inline butt stock and top hinged receiver.

Interestingly the T52E3 also shares several features of the Johnson Light Machine Gun, with the front sight post, handguard and pistol grip being used, they may have been for ease as the parts were available.  The T52E3 was an air-cooled, fast barrel change light machine gun with a front bi-pod.  It was chambered in the new T-65 cartridge (the 7.62mm round also used in the M14).  It had a cyclic rate of approximately 700 rounds per minute and was fed from a belt with disintegrating links.   The T52E3 prototype came in two barrel types a light weight barrel (Image One) which was envisioned to be the standard for infantry patrols and a heavy barrel (Image Five) which weighed 7 lbs which was intended for sustained fire.  

The M60 would replace the cumbersome 31 lbs M1919A6, weighing significantly less at 23 lbs.  The T52E3 would be refined further until it was finally put into production in 1957, it would first see active service in Vietnam in 1964.

Image Source and Further Information

Prototype: T24

The T24 was developed in 1943-44 by the US Army as a replacement light machine gun.  The photographs above were made at the Aberdeen Proving Ground in February 1944.  The T24 was infact a direct clone of the German MG42 but rather than being chambered in the German 7.92mm Mauser cartridge it was rechambered to fire the US' standard .30-06 round.  You can see the .30-06 rounds inserted into a German belt in the final photograph.

The gun is almost identical to the original German weapon except for the use of a US pattern bipod and M2 tripod- the sort used on the Browning 1919A6 and BAR.   As well as US stock flip up sights welded onto the weapons receiver.

The MG42 was chosen because of it's reputation as a flexible weapon capable of sustained fired, something the US' light machine guns lacked, and its high rate of fire - a staggering 1,200 rounds per minute.  It was the first true general purpose machine gun.  Such was the MG42's effectiveness Allied troops attacking German positions would wait for the brief pause in fire caused by belt and barrel changes.  It was a much feared weapon and was often nicknamed 'Hitler's buzzsaw'.  

The T24 however, suffered from a number of technical issues that prevented its further development.  It was found that by simply altering the weapons cartridge meant that it's bolt no longer travelled back far enough which lead to stoppages, the .30-06 round was longer than the original German cartridge. The T24 was abandoned in 1945 and development of other light machine guns such as the T44 began.  The later prototypes, which were heavily influenced by the MG42, later became the M60.

Image Source