[Travis McGee]

Cover, movement, shot placement and functional weapon reliability are 10X more critical than caliber.

That said, I like 5.56mm. It works from zero to several hundred yards, as far as I need. It goes through kevlar (oops!) With a quick finger it lays out close range lead like nobody's business. For its small size it makes a big wound. And you can carry twice as much 5.56mm as 7.62NATO/.308.

[Storm Orphan]

I'm finding that with my new HK-91A3 I can hit a good 200M beyond my best with an M-16/AR-15.

Given that, I figure the weight differential is of little consequence. (i.e.I can hit from futher away
than the other guy. Always a nice feeling.)

But I am new to 7.62 - so any insight would be welcome.

[lepton]

7.62*51 is better if one is dealing with cover, vehicles, or firing through structures or at ranges over 300m. 5.56 does odd things within 300m that make its damage suprising, but around 300m the round begins to turn into a double-weight .22LR. As you noted on another thread, you can only carry about half as much as you can 5.56. Also, the 5.56 weapon itself is generally lighter. 7.62 weapons are generally better, but not always, if you feel the need to use it as a club.