Almar, 45s work well. I milled for 24 hrs and no pile up. A small mill harbor freight only put in 100 and did a good job.
Doublebuck, update on the lexan plate in the 40 mm press. It started cracking due to a slight concave piston, my piston is hollow, I formed a spacer from a white plastic water barrel 3/16 thick and plenty tough. This keeps my piston loose after pressing a puck, I remove the bottom press plate press again till the puck is even with press bottom only a few taps and out the puck comes with out a stuck piston!
Graysmoke