Take deburring tool..... spin lightly in muzzle (kinda like brass)... Chuck done-headed slotted brass screw in drill... apply valve grinding compound to screw head.... Place screw on muzzle and run drill at moderate speed.

I've also used one of the Dremmel cone-shaped grinding bits spun by hand.... that seems to be the best way to do it.

You better pray to the God of Skinny Punks that this wind doesn't pick up......