I remember I developed a bunch of those burs when I pulled my patchworm thru the avenger an I had the shroud threads exposed now I just run a straw instead of unscrewing the adapter so thats how that got there just sanded em down after I noticed integrity decreases of some patches I pulled thru as the burs where pulling the strands on the patches when I was putting em on, So sometimes it would rip thru the patch an patch would be left in barrel an the worm pulls thru , You can just get a box cutter or something an debur it an sand it on that spot with some 400 grit or so should be good find out what caused em as it gotta rub against something sharp/rigid in my case it was the threads on the end of the shroud.
