barrel problem

okay so i just got a 12'' barrel that has a lot of musszle break at the end wich i wanted only problem is it has a lot of burr in a little further anyone have any idea how to fix this? im thinking of sanding it but then relized that causes grooves and grooves means spin possibly

if you can take it back and exchange it i would. Other than that not sure what to do.

took a dremmal to it and got it really carefully dam i wont ever buy a barrel from that guy again (as i flip off ebay lol)