No I'm not, but I'm saying if one is not very careful the steel threaded area on the brush can catch the crown before the nylon enters the crown/bore. I've seen damaged crowns and this is usually the only thing we've been able to attribute it to. Also some of your longer cleaning rods drag across the crown before this area also. The steel tip of the cleaning rod along with the steel threaded area of the brush can cause damage if one is not careful. I've seen guys go at it pretty aggressively with no attention paid to this.