Can you post a picture please? I just stripped my pistol and can't find anything similiar to that marking on mine. I'm curious..
The mark I did find was very shallow, as described, but looks more like a skinny "D".
Mine is very accurate, enough to put 3 shots in touching overlapping holes at 15 from a rest.
Ross Perot... err I mean Ron Paul '08!
Do not be overcome by evil, but overcome evil with good Romans 12:21