I believe for hunting purposes or if you're not loading to max powder charge it won't hurt. The reason I say this is that your accuracy will probably drop off using mixed case brands but not enough to substantially affect hunting accuracy (except at extreme ranges). Also, if you're loading below the max. recommended charge there is also no problems. (these charges are max for all cases) I've noticed when loading my .223 for my AR using mixed brass brands that there are some brands where the charge fills the entire case including the neck. These cases are discarded after spraying the primer with gun oil.