Check thru some of the older posts. There were some posts about the same issues, and some replies from cutter if I recall correctly about his experiences and what he got to work. He has a video posted this week on the progress page of his short barrel gun with a test stick mag that seems to work good. I seem to recall the slot needs to be a bit wider than the rim thickness than you might think, looser is better. They were posts within the last three or four months if that helps.
