Search:

I've never seen that issue myself and I usually tumble for two hours. I could see though for something like 6.5 Creed where people have nicely prepped their brass where that might happen.

Each method has it's flip side and ultrasonic doesn't agitate like a tumbler, so the ultrasonic seems to break the dirt loose but then you have to wipe it all down. I'd say after an ultrasonic bath...

I do it often and yeah it works but usually the primer pockets are not as clean.

My recipe is some Hornady case cleaning solution, some Lemishine(citric acid) and distilled water. Works great.