Type 100 grenade discharger

The Type 100 grenade discharger was introduced in 1939 as a grenade launcher for the Type 38 and Type 99 Arisaka rifles.

The launcher is somewhat unusual in that rather than using the more common cup designs it is a gas trap system, meaning that it incorporates a barrel extension which taps off excess propellant gases to launch the grenade from a cup offset from the barrel.

This has the advantage that standard rifle cartridges could be used along with the standard hand-grenades which simplified logistics, at the expense of increased weight and decreased efficiency.

The effective range is approximately 100 yards (91 m).

[1] This article about the military history of Japan is a stub.