It might be set with staking or soldering. A little item would be that the pin which retains the firing pin spring cap tended to operate loose, and had to be tapped again in place as 1 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/