Was cleaning a friend's winchester model 12 that looks like it's seen a good amount of use. I noticed a wear line inside the top of the receiver caused by the firing pin retractor (see photos), and on the retractor itself. I'm not surprised to see this, but it looks deep to me. Will this cause any function issues in it's present state or if it gets worse? Sorry I'm used to 870s...
-Shed
-Shed