Guess you have just not seen them, as they are there and as I said, Not to worry, everything is good as long as it goes bang!
Different then a firing pin slightly off center, but I once had a post 64 Winchester M 70 that had a tight spot in the barrel. Not a bulge, a tight spot. And much more recent, a Browning "A-Bolt" that had a barrel which looked like it had had a threading tap run down the bore.
Now that was something to be concern about, as even though they would both go, "bang" they shot VERY badly
Keep em coming!
Crusty Deary Ol'Coot