"about animals shot with regular .270 Winchesters using deer bullets - maybe not hit all that well - "

I believe this about says it all. The capabilities of all the various and sundry cartridges ranging from .277" up to .323" are pretty muchtotally dependent upon the design of the bullets that are used.

For example, not too many years ago, the great Elmer Keith was fond ofsaying "the .30/'06 is barely adequate for shooting jackrabbits," and "even the .30/40 Krag is a better killer of deer, elk, and moose than the .30/'06", etc. Actually he was basing this opinion on the fact that early on, the '06 was loaded with bullets which were too fragile for the higher velocities at which the '06 launched them. So although he was damning the cartreidge, his opinbion was actually based on poor bullet performance!

If you use a tough .277" bullet, such as the Nosler Partition or Barnes X, at .270 Win velocitiesor faster,you will be hard pressed to tell the differencein performance on game between it anda .30 or 8mm of comparable sectional density and constructionthat hits the same place! I have examined enough wound channels from rounds of this type over the years to know! Despite the fact that I own rifles in 7mm Rem. Mag., .308 Norma Mag., .375 H&H, 416 Rigby and .45/70, these days I find myself using a Ruger No. 1A 7X57mm with 175-grain Nosler bullets at a MV of 2720 FPS more and more for all game, and have yet to feel handicapped.