Hi Steve, as Holly says, if there is pitting it will collect lead, the accuracy will not be there and you will get flyers when the build up of lead sticks to a pellet. I had 3 walther barrels ruined by a company inexperienced with gun barrels attempting to blue them before I used Colin, I tried to salvage them, I spent hours polishing the best one to salvage just one of them but they all ended up in the bin. on the bright side many barrels are made from very good steels which don't rust easily, and a little surface staining should not have hurt it and polish out.
As for the cylinder, again if there is pitting it will be weakend but it would need to be in board of the cylinder end seal and too bad to polish out to render it scrap.
HFT, for people with only 2 buttucks!
VooDoo TwoTwo The next chapter.