It might be preset with staking or soldering. A little product would be that the pin which retains the firing pin spring cap tended to operate free, and needed to be tapped back again in place as a single observed it undertaking from the rear with the bolt. Winchester replaced https://highimpactrounds.com/product/winchester-m193-5-56-nato-55-gr-fmj-3180-fps-200-rd-box/