You could run them that long in a 10mm mag. I have a Trojan with Tripp 40 mags and at 1.17 with Zero 180gr JHP's I had to pull the spacer's out. I really messed up after loading a similar MG JHP, I just eyeballed and thought the Zero's were pretty much the same shape, boy was I wrong. I showed up at one of our monthly steel matches and almost didn't get to shoot, I had to not only pull the spacer's but I had to file the little pinch points that hold the spacer in place. I have run them in our local IPSC match and they ran fine. I guess I could really load them longer now I'll have to give them a shot.