/vr/ - Retro Games

>>5907657
Some guns can be ridiculously simple, to the point of genius.

If you look at old WW2 era and early Cold War SMGs, a lot of those are open-bolt blowback guns, meaning there's no locking system, there's no hammer, striker, or even a separate firing-pin, rather the firing-pin is a nub machined into the face of the bolt, which is basically just a solid weight, making sure the action stays closed long enough that it's safe to extract, but not so heavy that it prevents the action from opening at all.

You pull back the bolt until it catches on the sear, and it's now under spring tension, when you pull the trigger, the bolt is released, thrown forward, picks up a cartridge from the magazine, and puts it in the chamber.
Inertia makes sure the fixed firing-pin detonates the cartridge as soon as it's in the chamber, and pressure from the fired cartridge shoves back at the bolt, eventually overcoming its weight and throwing it back, the casing sticks on the face of the bolt as it travels back, hits a fixed piece of metal (the ejector), that makes it bounce out of the ejection port, and the bolt hits its rearmost point of travel.
By this point, if you had let go of the trigger after the last shot, the bolt catches on the sear and stays there until you pull the trigger again, or if you hold the trigger down, nothing stops the bolt from then being shoved forward by the recoil spring, and the bolt will continue slamming back and forth until you let go of the trigger, or your magazine is empty.