ACTUATOR: Cocking handle.
BLISH LOCK: An ‘H’ shaped device that locked the breech-block under pressure and helped reduce the high rate of fire.
BLOWBACK: Using the inertia of the breech-block to hold the cartridge in place at the moment of firing. Pressure generated then pushes the breech back to re-cock the weapon and repeat the cycle.
BLUED: A chemical process that turns bare steel a deep blue-black and helps prevent rusting.
BREECH-BLOCK: The component that closes the breech, usually a rectangular or conical machined piece of steel within which the firing pin and cartridge extractor are incorporated.
CUTTS COMPENSATOR: A slotted muzzle attachment that directs the fired gas upwards and/or sideways, helping reduce the tendency of the muzzle to rise on firing.
CYCLIC RATE: The theoretical rate of fire of an automatic weapon, assuming an uninterrupted supply of ammunition. Normally shown as rounds per minute [rpm]
FORE-END/FORE-GRIP: The front grip of a submachine gun or rifle.
PARKERIZED: A wartime form of blueing, but one that produced a matt, blue-grey finish.
PEEPSIGHT: A simple open rearsight, used mainly for close range shooting.
RECEIVER: The body of a weapon within which the breech-block travels.
RECOIL SPRING: Also known as the return spring. It is the spring in an automatic weapon that cushions the rearward movement of the breech-block, eventually returning it to its forward firing position.
SEAR: A small angled bar linked to the trigger which locates in a slot in the bolt or breech-block, holding it to the rear. When the trigger is pulled, the sear is released and the firing mechanism moves forward to ignite the cartridge.
SEMI-AUTOMATIC: A weapon that fires one shot and automatically re-cocks but will not fire a second shot until the trigger is pulled. Most submachine guns have a fire selector that enabled them to shoot in semi- or fully-automatic mode.