It could be fastened with staking or soldering. A little merchandise would be that the pin which retains the firing pin spring cap tended to operate loose, and had to be tapped back in place as a person noticed it venture within the rear on 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/