I just purchased a rifle from an auction site. It was a stainless T/C Greyhawk. When it arrived I ran a patch down the barrel and it came out rusty (really rusty!!). Apparently the previousl owner thought stainless rifles didn't have to be cleaned after shooting black powder. After looking at the bore there was severe pitting at the muzzle some pits were estimated .060 to .080 deep (big pits). I ran about 100 passes with JB bore paste just to see if I could smooth it up enought to see if it would even shoot. After the cleaning process the pits were still very obvious. I shot three shots with 80gr. Black Mag3 and 300gr. bullet/sabot. The three shots were very close less than a 2 inch spread which with iron sights and my old eyes surprisingly good. The final death blow however was when I pulled the nipple and found the threads erroded to the point that I felt fortunate that I didn't get a nipple in the face. Bottom line here is that a pitted barrel may shoot pretty good in spite of what it looks like. The guy I bought the rifle from was not aware of the condition as he was a dealer and didn't inspect the rifle before passing it on. He returned my money and I sent the rifle back.