It may be set with staking or soldering. A small item would be that the pin which retains the firing pin spring cap tended to work loose, and needed to be tapped back again in place as 1 observed it job through the rear from the bolt. Winchester replaced that https://highimpactrounds.com/product/winchester-aa-12-ga-2-75in-1-1-8-oz-8-lead-1145-fps-25-rd-box/