http://www.youtube.com/watch?v=EKlu-4mJm2E" onclick="window.open(this.href);return false;
This guy is not using enough media. Up at the top of the drum, you can see all the brass that is thrashing around on itself and not in the media. That beats up your case mouths. It's also noisy as hell. He needs to double hte amount of media in that drum so that all the brass is in the media.
Also, he's using a Kobalt plastic drum mixer, which is a "Red Lion" model rebranded...it's a crap design, with a plastic worm gear that drives the drum. The plastic drum will get soft in the sun and then it flops around on the lower support rollers. It works here, but not for really large loads. I run mine (Direct drive, all steel) with 15 gallons of walnut and 5-8 gallons of brass. I added a whole pint of NuFInish to the media when I first ran it. Now I add a cup of stoddard solvent to the drum with each new load. 3 hours and nice clean brass, and it's no louder than a clothes dyer. And my media still looks like new.