The AR have come a very long way and still getting better. I know a lot of the high end ones ($$$$$) have gone to a piston system rather than a gas tube. The M14s are heavy I have handled a modern version the M1A1 I am sure they are lighter than the originals. That 7.62 ammo is bulky to carry for sure. The AK 47 is anther great weapon that has stood the test of time although often used against our troops or newer versions of the rifle (AK74).