I had one. It was a jam-o-matic. The metal bits worked fine once adjusted it was the mags that were awful. They would get half way stuck coming out of the mag or nose up or down so that it wouldnt feed right.

I dont think it wasnt a dud mag either, it cane with 2 mags and both had the same problem. Kudos to centerfire systems for being cool with the return and trying to help me through the problem. Id buy from them again in a heartbeat.