Buzzcook: the only caliber requirements here are for buffalo. 41 Mag minimum.
CCCLVII: I do plan on using big hardcast bullets.
I ran across some ammo the other day that intrigued me. It had a 140 gr. FMJ truncated cone bullet. It's supposed to be for practice but its velocity is listed as well over 1400 fps. That load seems like it would penetrate well. Have any of you used anything like this?