however I would like to point out that military training doctrine states that if the target is beyond the maximum accepted range of iron sights(300 meters), generally you turn things over to the guy with a scope and bigger round anyway. there is no reason to look for a round that is more lethal past acceptable firing ranges in the first place but then again I have seen more taxpayer dollars spent in worse ways.
Gosh ..... things sure have changed in the .mil ...... As recently as the mid 90's, I was expected to hit targets at 400 meters with irons.....
.... and I've seen arguments right here on this forum both that the issue caliber is fine for places like A-Stan, where 50+% of engagemts begin past 500 meters, that the issue caliber is not any good past 200 meters, and that irons are useless past 300 ....... sometimes by the same people......
FWIW, I think the 6.8 is a better cartridge than the 5.56 for the kind of things the 5.56 is used for ...... it's still an intermediate cartridge.