It could be set with staking or soldering. A little merchandise would be that the pin which retains the firing pin spring cap tended to work unfastened, and had to be tapped again in place as one particular saw it job in the rear with the bolt. Winchester replaced that https://highimpactrounds.com/product/winchester-super-x-20-ga-2-75in-3-4-oz-rifled-hollow-point-slug-1600-fps-5-rd-box/