When working on the Accles drum a few months back I was having trouble with the rounds stacking up and not feeding evenly. I had contacted Paul a couple of months prior to his passing and he sent me a photo of what he found work by adding a second band inside the outer one to keep the rims of the cartridges upright and even. It has worked out well on my drum. I just found the photo and thought I might pass it on for what it is worth