I have a new to me 58 that appeared unfired when I bought it. The problem is from the start it will fail to rotate cylinder on average once per cylinder full. The gun is very clean and was cleaned again after problem arose. It fails on random chambers, not the same one every time. It does this in single action or double. The hand and hand spring seem fine, had a gunsmith check it out and after getting it back a month later same issue, he said he cleaned up ratchets on extractor, but no change. Any ideas on what might be problem? Any help or ideas appreciated.