If you attempted to unscrew a pinned on muzzle device, this service will repair the threads you stripped off in the process. We turn down, thread, and install new threads just like we do with the threaded extension service. This way you keep the barrel length. If you just want to cut off the damaged threads and shorten the barrel, that would be the $75 threading service. If sent as a complete upper, the Disassemble/Reassemble service is required as well. If the barrel is not “just the barrel”, that will fit through a round hole there is a $30 up charge.