I've been running a KUSA KP9B. I've got about 3000 rounds in without a malfunction. I'm using KUSA and Pufgun magazines. Ammunition has been 115 to 158 grain, every odd hollow point I had. I shot lead round nose and truncated reloads. A variety of steel cased as well as Blazer aluminum. I've had a blast shooting it at PCC competitions.