Quote Originally Posted by panhard View Post
My thoughts were that factory loaded cases would have been clean brass inside but I haven't got enough knowledge to know what difference the carbon build up will make. I like the idea of the dirt being rinsed away instead of accumulating in the tumbler media and also the primer pockets being cleaned at the same time. I've googled rock tumblers and ultra sonic cleaners and will give both more thought, not sure about sizes of either that I will need.

I used to use a US cleaner to get the spotless, eventually got bored of rinsing, drying, etc.

Now I tumble to clean up the outside ( notionally to stop the inside of my dies getting scratched) and have found bugger all difference in group size.

I haven't done a ES/SD velocity test but that would seem to be the way to set the issue aside one way or another.