[MeganC]

Just my $.02 but I’d guess that tradition had more to do with it than anything else. See, with muzzle loaders they carried them with the barrel pointing up so that the ball didn’t drop out of a loaded rifle. After breech loaders came along they just kept carrying them that way because it was a tradition.

The Old Guard at the Tomb of the Unknown Soldier carries their weapons the old way.

And somewhere along the line someone with some sense realized that tradition is fine for the parade ground but utterly pointless on the battle ground, thus the update to weapons carrying tactics.

Again, just my $.02

[dblshot]

Shotguns are carried at port arms when bird hunting because it is easier to bring the butt to your shoulder when tracking a bird. The M1 was not a spray and pray weapon, one actually had to bring it ones shoulder to sight so port arms supports this move. M16’s are more accurately fired in the butt to shoulder position but I think we can surmise from the 10000 rounds to one kill ratio in Vietnam that accuracy was a second thought except for snipers who didn't use plastic guns that go boing when the spring compresses. OTOH M1 weight is more than an M16 and as noted above the iron in them rusts fast.

[A.A. Cunningham]

The Old Guard at the Tomb of the Unknown Soldier carries their weapons the old way.

They aren't out on patrol locked and loaded in the bush and right or left shoulder arms or port arms or present arms is SOP when walking a post.