It may be fastened with staking or soldering. A small product would be that the pin which retains the firing pin spring cap tended to work unfastened, and needed to be tapped back in place as a person observed it venture within the rear from the bolt. Winchester replaced that https://highimpactrounds.com/product/winchester-target-7-62x39-123-gr-fmj-2355-fps-20-rd-box/