I'm sure my experience is an outlier, but I bought a used EZ. Tried different ammo brands and weights, and couldn't get one single mag to run without a failure to feed or sometimes to go into battery. One of the guys I shoot with also had one that he sent back to the factory... twice... had a local gunsmith work on it, and it still wasn't reliable for the same reasons. We both sold ours. My suggestion is to buy a new one (definitely NOT a used one 'cause you might get one of our lemons), or better yet, get the new Equalizer. Just my .02