It may be preset with staking or soldering. A small product is that the pin which retains the firing pin spring cap tended to operate free, and needed to be tapped back in place as just one noticed it project through the rear with the bolt. Winchester replaced that pin https://highimpactrounds.com/product/winchester-ammunition-long-beard-xr-20-gauge-3in-6-1-1-4-oz-shot-lok-lead-1000fps-10-rd-box/