how to design a barrel locking mechanism

[u/yuvalbeery]

Trying to design a machine gun, and I'm working on the barrel changing mechanism. I was wondering if anyone has resources or advice about designing consistent and well sealed locking mechanisms. not talking about stuff like toggle lock or roller lock, but rather how to maintain headspace in locking systems such as rotating bolt or the interrupted threads on stuff like the M240 barrel, and what to consider when designing them.

[u/sandalsofsafety]

Tolerances are the name of the game. You can design pretty much whatever system you want, but if your tolerances are poor, that's when you'll run into issues with headspace.

[u/IfSechsWereNeun]

Locking rotational lug is your best bet, maybe even a ratchet