I recently got the full sized Frankford Arsenal Rotary Tumbler (FART) and went to calculate the maximum amount of brass I could tumble in a load. The instructions say that the weight of the drum, brass, water, and media cannot be more that 30 pounds. I got out the kitchen scale and found that the large drum weighs 3# 3oz with the caps in place. The maximum volume is 7 liters. Now if you start out with the drum full (7 liters) and start adding brass the level of water in the drum will go up and the excess should be discarded to keep the maximum volume at 7 liters. After accounting for the overflow the maximum amount of brass came out to be 12# 14oz. (Note for the curious -- the amount of water in the drum went from 7 liters down to 6.3 liters.)
I don't like counting brass any more than I have to so I got out my old one pound coffee can and and did count how many of the calibers I normally load for (38spl, 45acp, and .223) it would hold. It turned out that 4 cans of any of these would be less that the 12# 14oz max load.
i realize that I will need to redo the calculations when (if) I start using the SS pins.
Although I don't have the FART Lite I would like to run the calculation for it. I would appreciate it if someone would weigh their FART Lite drum and post the results.
Note to those doing the calculations themselves. There are sites that give the number if cartridges per pound for many of the common calibers and my old Butternut coffee can holds 1 liter of water.