Springfield Armory’s Rifle, Caliber .30, T20
When the Infantry Board formally requested an automatic version of the M1 rifle in September of 1944, the Ordnance Department responded by informing them that they had already begun to develop a select-fire version of the M1 rifle back in May of 1944. The select-fire M1 under development at the Springfield Armory was designated as the T20 rifle. The first T20 select-fire M1 rifle was delivered to Aberdeen Proving Ground in early November 1944. The weapon’s select-fire operation was achieved by means of an independent sear release actuated by a connector operating off of a cam located on the operating slide. The T20 design attempted to use a closed bolt operation for semiautomatic fire and an open bolt for automatic fire. Other problems plagued the T20 rifle. Due to extreme heat generated by automatic fire, the wooden foregrip would get hot enough to char during extended firing. Excessive recoil generated by the powerful .30 caliber cartridge also proved to be a major problem. To aid in control of muzzle rise, John Garand designed a series of muzzle brakes. Though they proved effective in controlling muzzle climb, there were several problems with John Garand’s designs. The first muzzle brake design required a redesigned gas cylinder lock, and with that device installed on the barrel a bayonet or a grenade launcher could not be used on the rifle. Subsequent T20 variations had redesigned muzzle brakes that did permit the attachment of a bayonet or grenade launcher.