In the 1000 rounds of UMC that's been through my G19, only one was a problem. The round jammed my gun up so badly, it took 2 people to rack the slide back and eject the round. When I examined it, the brass case was "peeled" back about 1/8". This was not a limp-wrist or any other shooter-induced jam, it just kinda happened. I still buy UMC today, if Wally World runs out of Winchester anyway .