I'm not sure honestly. I've loaded over 100K of the same load on the same machine over the last 5 years and have never had any rounds tumble. But, they seem to do so in the Trojan. They run fine out of my CZ's, Glocks, M&P's etc but for whatever reason the STI doesn't like them. It feeds and shoots them fine but the groups aren't very good and about 1 in 3 will have a slight tumble. I hate to think I can shoot better groups with my carry Glock 19 than I can with this gun. So far, that is the case.