Page:Machine-gun tactics (IA machineguntactic00appl).pdf/267



Diagram of Japanese Machine Gun—Tripod Mount.

a-b Front and Rear Sights A  Piston rod m  Gas Vent. e  Gas chamber. d  Regulating nut. e  Strong spiral spring. s  Feed Slot R  Radiator

piston and not by the direct force of recoil as in the Maxim. It uses the same ammunition as the infantry rifle (murata calibre ·26), and is rated as firing 600 rounds a minute. Two forms of mountings are employed, the tripod and the wheeled; the former for fortress use, and the latter for mobile troops. Referring to the plate, a gas vent m communicates with a gas chamber c attached laterally to the barrel. The pressure in the gas chamber is regulated, within limits, by the nut d, which varies the capacity of the chamber. The piston-rod A is acted upon by the gas pressure at its forward end, and is driven to the rear against a strong spiral spring o, which moves the piston end forward after the gas pressure has ceased to act. The reciprocating motion of the piston-rod actuates the mechanism, which is entirely enclosed in the housing, and performs the various operations of feeding, firing, and ejecting through a suitable train of gearing. Cooling is effected by the radiator R, a circumferentially