I have the HF Dual Drum Rotary Rock Tumbler which is fine just too small and need to do a lot of loads. I am thinking of picking up a tread mill for free and using like 5 gallon buckets as a tumbler. That way I could do 10 lbs of casings at a time. Has anyone else used a treadmill or what did you come up with. Also is there a good 5 gallon container with a locking lead so it won't leak?