Make sure it's empty, get a flashlight and look down it. You should be able to make out the rifling very easily. If it's really black or tough to spot the rifling, you might want to pass on it, but who knows, sometimes they still shoot just fine. It's a good idea to patch the barrel before you look. The condition of the muzzle end is the most important part of the barrel. Check for dings and abrasion. Dings you can fix sometimes by recrowning. Abrasion is another matter.
Ty
