I've got two .270s now, one has a 24" barrel and the other has a 22" pipe. The three other .270s I've owned have had 22" barrels, too.
I've not been able to see any difference in killing deer with either barrel length. Neither seem to have any problems knocking a deer well and truly dead.
I don't even see any difference at the chronograph, perhaps my 24" pipe is a bit "slow", or the 22" pipes are a bit fast, who knows?
The Model 70 seems to balance better for ME with the 24" pipe, so I've kept it at that length. The Howa seems to work well enough with its shorter barrel.
Deer don't seem to care either way, nor do I. I use the same loads in both rifles, out of the same box, even. A good load with good bullets, kills deer just fine. I don't hunt elk, or moose, but my deer die quick and easy with the 6.8, no problems. I don't even have to worry about bullets, all the .277" bullets I've used kill stuff dead enough.
