I've been looking at this. Question. Would you buy a 308 or 30.06? Which ammo is (will be) more available?
1) .30-06 is still the most common center fire cartridge sold in USA
2) A weapon (ie. a M-1 Garand) in .30-06 CAN FIRE .308 in a pinch WITH AN ADAPTER installed in the bore w/permatex. The reverse is of course not true. When raiding for Ammo post-apocalypse you can grab BOTH.
3) AP m2 in .30-06 is LEGAL TO OWN and NOT LEGALLY an ammor piercing round per ATF fed gov reg. Remember it is NOT ARMOR PIERCING per ATF.
4) No doubt, .308 win is an awseome cartridge and many VERY reliable weapons offered. If I wasn't an M-1 guy I'd have an ar-10, m-14, or FAL.
5) (shameless plug for Garand follows): the M-1 is legal to own in all fifty states and such horrid places as Chicago, San Fran, New York and even CANADA. It will likely be off the radar screen even for Nancy P. and Company. But apart from that, the CMP will still sell you one (with some miles on it) and plenty of ammo for a relative song.
And then buy a nice new SOCOM II from the folks in Geneseo, IL because they deserve our business before they are run out of Illinois along with Armalite by Gov BLAGO and Daley.