.308 is identical in diameter to the 7.62x51 NATO cartridge (although the two are not exactly the same). .223 is identical in diameter to the 5.56x45 NATO (and M193) cartridge (though, again, they are not exactly the same). The .308 is larger.
.308. which is 7.62
308...A 7.62mm = .300
400
308 is more than 8 times the size of 37.
No
lighter bullet and more ammo can be carried as opposed to the 30/06 or 308
Yes. Significantly.
556
556 * 556 = 309,136
Both fire the same diameter projectile.
No. Both use the same diameter projectiles.
30-06 because it's a bigger round than the .308 although it might travel slow it has greater impact on the target