M27 105mm Recoilless Rifle
Recoilless rifles are capable of firing artillery-type shells at velocities, and with an accuracy, comparable to those of standard guns, but almost entirely without recoil. The 105 mm M27 recoilless rifle proved to be lacking in accuracy as well as reliability and was soon put out of service. Soon, the M27 was redesigned as the M40 and, to avoid confusion and to also prevent use of the M27 ammunition still in stocks in the new weapon, the M40 was classified as a "106mm" weapon.
The standard M40 is the M40A1 and it has, since its debut, been highly successful in the military arsenals of countries, rich and poor, around the world. The M40A1 is 340cm long from breech to barrel tip and weighs 209.5kg in firing order. Three types of ammunition are provided and they are: HEAT, HESH, and a anti-personnel round, the HEAT round able to penetrate up to 150mm of armor at a 60 degree angle of impact. The maximum range for the M40A1 is 7,700 meters but the effective range is around 2,750 meters with a muzzle velocity of 500 meters per second.
In September 1970 three TOW training battalions became operational, replacing the M40 106mm recoilless rifle and the French ENTAC. By 30 September, the Army had completed phaseout of the ENTAC after the TOW missile was standardized. The M40 106mm rifle was redistributed to the reserves and depot stocks as it was replaced by the TOW.
