It may be mounted with staking or soldering. A little item would be that the pin which retains the firing pin spring cap tended to operate loose, and needed to be tapped back again in place as a single saw it challenge with the rear in the bolt. Winchester replaced https://highimpactrounds.com/product/winchester-super-x-20-ga-2-75in-20-pellets-3-buck-1200-fps-5-rd-box/