I've always looked at the two in terms of use, carry weight and barrel length. The 270 Win stands out as a nice to carry 6 lbs rifle with 21 or 22 inch barrel giving great MV with that length and making a fine mountain carry rifle able to dispatch bull elk at good distance while maintaining needed ME. The 7mm RM could be reduced somewhat in weight to supply ability for same task in mountains, but would be heavier by a pound or more needing a 24-inch barrel minimum to make a real ballistic advantage over the 270 Win. The 7mm RM comes into its own when utilizing a 26-inch barrel for the likes of pronghorn and mule deer. A 140 grain BT or AB at 3,400+ fps is a nice advantage out in western Nebraska, Wyoming and New Mexico. The 7mm RM is as good as it gets when equipped with a 26-inch barrel for taking long shots with reduced holdover and doping. I have a 308 Win for the mountains and whitetail use and use the 7mm RM exclusively on pronghorn and mule deer in Wyoming and western Nebraska. For elk I typically use a 338 WM but like the 308 Win as well. With the advent of the 6.5mm craze, which is well deserved, the 270 Win and 308 Win are still legitimate contenders in the field and can certainly hold their own against the rest.
