Jason, I would use the 139 Hornady Interlock, but only in the flatbase configuration, if you plan to hunt with it. The boattails seem to act much like a varmint bullet, if you hit bone. In the several 7x57's I've owned, and in my Ruger 77 280 Rem, this bullet has proven to be one of the most accurate. The Sierra bullet would probably be my choice for accuracy overall, but every one of them I've tried on game, seemed to blowup immediately on contact. Just my 2 cents.
Regards,
Woody