It could be set with staking or soldering. A little merchandise is that the pin which retains the firing pin spring cap tended to operate loose, and needed to be tapped back again in place as one noticed it venture within the rear in the bolt. Winchester replaced that pin https://highimpactrounds.com/product/winchester-xpert-20-ga-2-75in-6-3-4-oz-1325-fps-game-load-25-rd-box/