Interesting advice from Precision Rifle muzzleloader bullets guys in Canada. They said, if buying a used savage, smokeless ML, be sure to check that a saboted bullet goes down the barrel with consistant resistance the whole way. If previous owner double loaded it by mistake, it could have a slight bulge that you could notice via a "no or little resistance" spot when seating the bullet. He said if that is the case, the barrel has been compromised and the next time somebody makes a mistake by over charging or double charging w 2 bullets, the gun could easily rupture and cause injury.
Thankfully, mine shows no such concerns. Cleaned it up, ordered new vent liners, and looking forward to shooting it soon.