you made lots of things weigh practically zero! and you had springs with a constant of 60 thousand! so when the bullet recoils it throws the bolt and hammer out of the gun!
i do not want to post my version because then it will look like i made it, but my suggestion is use heavy parts! and adjust everything around that.
i have to say though, im glad to see a gun that works realistically unlike yuras12's ones which is just a spinning wheel with a fancy skin.
