Sticking to the three choices, you really need to be careful, with all three of them at the 400 yard specified maximum difference.
All three of the cartridges mentioned will kill a Moose/Elk/Bear/Deer out to that range as long as the shooter does their part, especially regarding accuracy and bullet choice.
If you insist on taking, what IMHO is an unethcal shot out to 400 yards, my choice would be the 30-06 with 185-200 grain bullets, loaded for the best accuracy with the highest velocities you can handle.
Heavy bullets is where the 30-06 overcomes the 308Win. It has enough extended powder capacity to drive such bullets fast enough to keep trajectories within manageable/useful parameters.
The next choice would be the 270Win, again with long/heavy bullets, loaded for accuracy and the highest velocities you can handle.
With both cartridges, the 30-06 loaded with 200 grain bullets and the 270Win with 160 grain bullets you can quite easily and safely, depending on the make/model of your firearms, achieve 2900fps and IMHO, both will have achieve great penetration and proper expansion at the extended 400 yard range.
When it comes to heavy bullets, the 308Win is a bit of a laggard at long distances. With bullet weights of 165grain and under, it will easily equal the performances of the 30-06 and 270Win when all else is equal, especially barrel length.
Far to often people compare cartridge performance against other firearms with shorter or longer barrels. This is done by writers to get positive results for manufacturers, when they write articles about such things in magazines.
270Win, 160 gr bullet, 2900fps, 200yd zero = 20in drop at 400yds.
30-06, 200 gr bullet, 2900fps, 200yd zero = 20in drop at 400yds
308Win, 200 gr bullet, 2500fps, 200yd zero = 29in drop at 400yds.
All of these velocities can easily be achieved out of 24-26 inch barrels.
i have both a 30 06 and 270, sold the 308 years ago as it didn't do anything better than my 3006...the 3006 is the one I grab for year after year... 7 deer and a moose so far
308 is just a slower 3006..yea smaller action.. sometimes (tikka?)...but I prefer the extra velocity, which means a little extra range and terminal performance of the 30 06.
270 works great too and if you are recoil-sensitive it may be a good option...it does have better sectional density, but is more limited in bullet selection in terms of weights. flies a little flatter than the 30s if you hunting open areas.
they are all so close in performance its hardly worth having a debate over, they will all kill moose with a good bullet in the right spot... a better question is what's stocked in your local community gun store.
a better question is what's stocked in your local community gun store.
I like 270’and 06 myself. However, my expensive 270 kicks like w mule, my el cheapo Remington 770 in 06 has 0.70 moa at 100 m and that is hard to discount on top the kick is a bit lighter than my 270.
He 06 took 2 moose so far at 375m and 350m, 2 shots each. Number of deer. So it grew on me lol
However, Im trying to talk myself into buying 308not because I need it, but because I want it.
All 3 are more than enough for Ontario, but is there a such thing as enough guns?![]()
Interesting that your 270 kicks more than your 3006. Lighter rifle perhaps?
As for whether there is such a thing as enough guns? For sure. There is no such thing at TOO MANY guns though.
I like velocity, and 30cals just don't do anything for me (too common perhaps?) so the 270 gets my vote. With a good 130-140gr bonded bullet the 270 is going to do just fine on Elk or Moose, and the higher velocity is going to ensure reliable expansion even out at 400yds. (whereas the 308 in particular is likely to be under 2000fps by 400yds, which is my personal minimum goal for expansion with the bullets I shoot. Manufacturers mostly claim 1800fps for what I'm shooting, but I like a bit of margin on that).