CWes, Since you have the barrel (even if you don't end up using that one) just slip your gas cylinder on it, screw on the brake, and see how much interference you've got with your gas plug. On mine, I used a straight shouldered burr in my dremel, and only had to relieve a small amount on the two edges of the brake at the back where the radius cut meets the shoulder where the gas plug seats. I used a little layout dye to double check that there was no interference. I didn't have to remove much material at all.