I have a 45 year old High Standard Citation that I bought used 40 years ago and shot thousands of rounds thru it. Replaced firing pin 10 years ago because it had the edge knocked off. It shoots fine. But I know that the bull barrel is worn to some extent. #1. how can I tell if it is worn so much to affect its accuracy? #2. Where do I get a replacement barrel? (I know I can get them online but are used and I don't know if they are in any better shape than mine). I have old Remington 22 rifles that I don't worry about because they have not had any way near the same amount of rounds shot thru them as my pistol. But a barrel has to wear out eventually.