Around 1970 I saw an advertisment for the little gadget shown, used for cleaning the muzzle brake. I was shooting competitively, and had a hard time getting the leading out of the brake. At that time we hadn't yet got the word that the brake degraded accuracy. I ordered one, and it was a long time in arriving: they said they had problems with the packaging not being to their specifications. The gadget works quite well, and I've never seen another one.