Re: Is it common to have bad machining on GP100?
Are all six locking grooves like that?
If so, I'd venture a guess that either the hand is over-rotating the cylinder and forcing the bolt against the far edge of the groove, or the bolt is unlocking late and the hand is turning the cylinder before the bolt is fully out of the way. I'm thinking the latter would be the most likely case.
The hiccup on the barrel shroud (by the ejector rod cutout) isn't normal. Haven't seen anything that noticable on a NIB Ruger before. From the pic you've got, to me it looks like it's dinged up by a tool and not machine marks. It might look differnt from another angle.