It may be fastened with staking or soldering. A little product is that the pin which retains the firing pin spring cap tended to operate unfastened, and needed to be tapped back in place as one particular observed it challenge in the rear on the bolt. Winchester replaced that pin https://highimpactrounds.com/product/winchester-target-223-rem-55-gr-fmj-3240-fps-20-rd-box/