All 3 of my Rugers show the same thing.
Let's step back and think this whole thing thru.
If you have 2 steel pieces that are expected to slam together, eventually one of them is going to give. If the bolt is the piece that gives, it will peen and become too large to slide through the reciever. Unless of course, you build some "slop" into it from the beginning. "Slop" translates into inaccurate, so that's not the way to go.
If the breechface is the softer of the two, then it can sacrifice itself without any real negative effects. Matter of fact, it should actually make things better,, within reason. As the breechface "dishes", it provides a more stable receptacle for the bolt to rest in when in battery. It's really nothing more than a seating in process. That should translate into more shot to shot consistancy.
By coincidence,,or by design,,that seems to be exactly the case. All three of my Rugers have shown improvements in accuracy as the number of rounds fired have increased. My .22/45, which has over 35K rounds is more accurate now than it was when new.
The only thing to really watch for on the breechface of any Ruger is something beyond a "shadow" where the firing pin strikes. I let my 35K round .22/45 go just a few too many rounds w/out replacing the firing pin. Knowing now, what I didn't know then, I plan on replacing the firing pins on the other 2 when they begin to show a "shadow" on the breechface,,,or better yet,,,at ~ 20K/25K rounds.
The same steel vs steel action takes place between the firing pin and the firing pin stop. In the case of the bolt/breech, it's cosmetic and desireable. W/the firing pin/firing pin stop, the end result is a firing pin that can dig out the breechface.
Bottom line here is just enjoy shooting it,,be extra careful of the muzzle crown when cleaning it,,,and enjoy the added accuracy as it seats in. After all, ya only see the footprint when the bolts open right? Jus make sure you keep it well stocked w/ammo, and the bolt closed on an about to be fired round as often as possible
