The Model A-R2 No. 115 is the current version of the one I got decades ago. I bought it at a gun show but it didn't have the barrels with it.
Took a metal 40-ounce coffee can and made a rectangular liner for it out of 3/8" thick foam as wide as the inside of the coffee can is tall and as long as the circumference of the can. Made a round foam liner to fit the bottom of the can. Used duct tape to hold the ends of the liner together.
Put friction tape on the outside of the can that lined up with the rubber rollers on the driving and coasting rods. I've had it since the late 1960's. Had to replace the rubber rollers a few years ago but Thumbler's had them in stock as well as the nylon bushings that fit the rods to the base.
Recently taped two coffee cans together (bottom of one cut out) to have twice the capacity and lined it with 1/8" thick rubber foam for tumbling fired cases with media (rice and BB's) to clean them. Built a larger base to hold them and the drive motor, but it's worth it. I put one empty can with the foam lined one to use on the larger base so they'll stay in place.
Two-can rifle case cleaner's in place on the rollers. Red top single can's set up to tumble pistol cases, blue-green topped one's foam lined for lubing cases. Note four rows of friction tape on the blue-green top one; it doesn't weigh much with foam and cases inside so I had to double the friction from rollers to can. The other cans have media and cases in them when used and they put enough weight on the rollers.
Look closely at the nail driven into the base at the bottom right part of the two-can one in the other picture. It just touches the can's rim. Another nail at the top next to the red cover is also in place. These two nails keep the cans in place so they don't move the tape off the rollers. And they also keep the cover in place so the media and cases won't fall out and make one huge mess with the motor running. That happened once; years ago and I didn't want to clean up another mess again. Best use of nails I've ever driven into something.