I use the RCBS Rock Chucker Priming assembly. It works pretty well. Occasionally lose a primer during use so now have a piece of carpet under the press, they don't bounce / roll so much.

I have both the 20 and 29 , both gen 4. I prefer the 29, it conceals like my M&P 40C but has more oomph in the event i run into a black bear. I may actually sell the 20.

I just bought a new Glock 20 Gen 4. Waiting for KKM barrel and Comp-tac Infidel Hybrid. Will probably put some rounds downrange tomorrow. I'm hoping my stuff arrives today so I can test it all when I hit the range.