M129 grenade launcher

The M129 is a 40 mm automatic grenade launcher that was used as an aircraft weapon in United States service. It was developed from the earlier M75 and was capable of using both the high-velocity 40x53 mm grenade and the lower velocity 40x46 mm grenade.

Country Name Origin Year
United States of America 1966
Country Name Operational Year Retirement Year
United States of America View

The M129 was effectively a redesign of the older M75 to incorporate a concentric cam and improved mount. The major problem with the M75 was the torque created due to the barrel being below the operating drum. In the M129, the barrel is concentric with the drum and the excessive torque is thus eliminated. Otherwise, operation of the weapon is extremely similar to that of the M75, with the reciprocating barrel and cam assembly still presenting itself, the weapon still being electrically driven and ammunition still fed through a belt system. Some other improvements were made to the M129, most notably that of the addition of special feed tray to permit the firing of low-velocity and high-velocity ammunition, a mechanism to provide instant interchange between electric operation and manual hand-crank operation and a dynamic braking unit to guarantee that the launcher barrel always stopped in the forward (safe) position when the firing trigger is released.

Type Automatic grenade launcher
Place of origin  United States
Service history
Used by  United States
Wars Vietnam War
Production history
Designer Philco-Ford
Designed 1966
Number built over 1,667
Length 597 mm
Barrel length 419 mm
Cartridge 40x53mm grenade, 40x46mm grenade
Caliber 40 mm
Action Automatic, motor driven
Rate of fire 400 rpm
Muzzle velocity 850 feet per second (260 m/s)
Effective firing range 2,045 yards (1,870 m)
Feed system belt

End notes