I've only loaded them in the 6.5/.264 caliber. They are twist-specific. I found them easy to develop load for, and they are the most accurate bullet I've ever shot. I have not yet used them on game. Cooper Firearms and Weatherby seem to like them, as Cooper uses them for their test targets, and Weatherby sells factory ammo loaded with them.
I have a Cooper 6.5-284 I just got and a Cooper 6.5PRC, both grouped at Cooper using the 124HH. Do you mind sharing your 6.5-284 load?
