It may be mounted with staking or soldering. A small merchandise would be that the pin which retains the firing pin spring cap tended to operate unfastened, and needed to be tapped back in place as 1 saw it undertaking through the rear with the bolt. Winchester replaced that pin https://highimpactrounds.com/product/winchester-super-x-270-win-150-gr-power-point-2850-fps-20-rd-box/