All three cartridges are nearly identical in both power and recoil. The most noticable difference between the three is that the .308 can be had in a " short action" rifle, thus being slightly lighter and shorter than either the " 06" or the .270. So the greatest advantage of the .308 is it' s shorter overall length. Actually when you compare ballistics tables by picking different bullets/weights/designs these three different cartridges actually " overlap" power and recoil levels. I will say that a primary advantage of either of the .30 caliber on elk is their bigger diameter. With all other things being equal (though they always are not) the larger caliber will transmit more shock. But any of the three will kill elk!