I have many thousands of rounds through the Super Sport I pictured above, I should have stated that the marks and wear don't seem excessive at all to me. If it bothered me at all I suppose I could take a file and sandpaper to it.
I've shot thousands of rounds of target loads through my M4 on the skeet field. Finally this last year I had a few jams one day, took it home and pulled the pistons out, scrubbed the carbon off, and she's as good as new.
I love shooting skeet with my M4, it's a hoot to out shoot some grumpy snob with a Kreighoff.
That said, you can't have to many shotguns, can you?
I have a Super Sport that has many thousands of rounds through it that I broke clays with before I started having fun with the M4.