I can see the more rounds per pound issue though.
I took my M-1 garand out of the safe yesterday and was out of breath carrying it upstairs...not being young anymore I have an excuse, but still, you hike all day with an 11 lb weapon, and I can see you wanting to dump it for a 7 lb weapon with the ability to carry a whole bunch of extra ammo.
.308 is a strong round. 30.06 is a lot stronger.
Apparently, and I am not at all sure of the actual metrics, but I have been recently instructed that the two rounds are not quite identical, and one should not use the MILSPEC ammo in a civilian .308. Or is it vice-versa?
I date back to the M-14, and also have hunted with a .308. The .308 is a great round, and easily available in all kinds of interesting loads.