I had a swell in the barrel about 6 inches from the muzzle end so I was able to cut the length to 16 1/2 in. and fit up a new barrel extension for the AR15. It appears to be perfect for varmint hunting with the 204 Ruger shell , Krieger 1/12 , #2 weight , and 32 Gr bullets. It grouped about 1 1/2 inches last week. Just a quick change out in the AR15, but the factory shells are too expensive.