I’m not sure if it was nu finish or something else that I put in my media and had problems with the media clumping up inside. I’ll have to look when I’m home. But with just plain ole media, Something like this, I’ve had no issues. The inside of the brass doesn’t get clean like it does from wet tumbling, but that doesn’t bother me. The only issue dry tumbling media gives me is if for some reason I tumble deprimed brass, it gets stuck in the flash hole.I used to put a bit of NuFinish in but I quit to see if that was causing the problem. It still happens???
I use walnut lizard bedding.
It would be really odd if I'm the only one this has happened to. I can't help but wonder how many have this problem and don't know it.
It is possible that many are like I was, I had no idea I had media residue in my cases until I started cleaning the inside with a rotating brush.