had a problem with bullets tumbling in my g27. sent a box of ammo back to winchester to be tested and they called today. said there wasn't any problems with a smith but they did experience some "yawing" (sic?) with a glock. went on to say my problem may be that i'm shooting a glock. i know one brand of ammo that will never get bought or fired in anything i own ever again. on the other hand my sons issue duty ammo is winchester and he carries the same thing in his g27 BUG.