Initially I didn't want to reply because I knew I'd get jumped by folks. This isn't mule deer or proghorn...you are talking about a much bigger and much tougher animal. Yes, I know everyone realizes this. I personally think an elk deserves a tougher bullet than what has been proposed...for two reasons. 1) there are much better choices and 2) prepare for the worst...not every shot ends up being a perfect broadside shot.
I've seen the 223 with 55 FMJs used successfully more than once on our big northern moose. I also know that a person really needs nothing more than a 22 mag for these big
elg if you know what you're doing and use some discretion in choosing your shots. Then again, I once had an opportunity to try my new 340 Weatherby on a big bull in a classic broadside presentation. I placed 3 200 NBTs behind the shoulder- missing the big bones- and all were recovered against the hide on the far side. All were lethal, but a classic broadside isn't much of a test for a 340 considering that the same presentation can be as readily handled with just about anything else too.
The bottom line question hinges on how a fellow hunts the quarry in question. If you're willing to wait for another day to get the shot you need, go for it. If you'll use the bullet (and cartridge) in question to take whatever shot you've got today, then something tougher would seem prudent.
