While I like and prefer the .45 cal to the .30 - I still would not feel undergunned on most NA game with an '06. I've used one and know it's capabilities - I just prefer the larger hole.

I would never use one of the 300gr. factory .45/70's on any game as I handload everything I shoot - have to handload most of what I shoot & prefer cast bullets where I can.

I think .45/70 big game bullets start at 350gr., as in the Hornady RN and FN, although the newer Nosler Partition 300gr. certainly has shown well on a variety of game and penetration tests.

The .30/06, for me, is a long range deer ctg. with 165gr. bullets running 3,000fps. For heavy game, I prefer larger bullets - period, and buffalo ctgs. start at .366" and rapidly get larger.