[Leisler]

Bullet to bullet that is true, but you go heavier, and you'll start getting reports of guys running out of rounds.Suppression fire in support of movement over open terrine is vital. That requires lots of rounds. Weight. Real world is compromises.

The Army has been scientifically doing studies, taking reports and digging bullets out of bodies for 60 years now. What troops have is based on science, physics, logistics, experience over a wide range of real worlds shooting environments. The 5.56 is it.

If the Marines didn't think so, they'd tell the Army to f off.

[KoRn]

"The Army has been scientifically doing studies, taking reports and digging bullets out of bodies for 60 years now."

Everytime I wonder why they use the 5.56 that fact always comes to mind. There are other factors to consider aside from the ballistics. I suppose this is why we see the same arguments between .45 vs the 9MM for close quarters combat. Sure the .45 is superior for stopping power, but the 9MM can be used for both MP5s and sidearms. That allows them to carry the same ammo for two weapons. Of course they could use .45 subguns and pistols, or even .40s, but you get the idea. Logistics are an important consideration, and weight is one of those considerations, as you said.