For anybody interested, this is a simplified version of the BSA single shot tray. I'll load the model files (inventor part files) to the grabCAD website tomorrow. I can also put up stl files if anyone wants. It's very simple - I'm not a machinist or CAD jockey. But I've tested it with over 100 pellets (all diabolo style) on 3 different printed copies from 2 different 3d printers, so it's functional. The two pieces are attached by a countersunk 4-40 screw that passes through the magazine and threads into the swing arm.