I'm about to never enter the Rifle Section of The High Road Again. There needs to be a sticky; Take your AR Questions to ARF.com.
HERE IS THE REAL DEAL From the mouth of a man, who is Currently holding the Billet of "Infantry Weapons Instructor". I go through more ammo per month than most see in a live time, to the tune of 200k to 500k rounds per month. The Famous 5.56mm, M885-SS109, Penetrator ammo, 62 grain with steel tipped penatrating core ammo, that the US Military uses in Combat and Training, is a 'good round'. There are better rounds on the market. But can they be mass produced with the same cost effectiveness, can they be supplied at the same rate and will they slide through armored plate steel and kevlar like the M885 will?
There was a bit of a gap missing from training in the US Military Pre-Iraq War. The Marine Corps was focused on a 200,300 & 500 yard annual qualification, with a morning of field fire, that was pretty much a waste of ammo and time, good standard, good tradition, good training in a perfect enviroment, good confidence booster... Not enough for 4th Generation Warfare. Now some "special types of warriors" got to do the cool shoot houses and live fire ranges, the Combat Arms community has always done life fire squad rushes, and movement ranges, but everyone wasn't put through a 'combat' 0-50 yard type range, not everyone was trained to engage each target with 2 rounds first, and follow the target to the ground or keep engageing other targets and then reasses.
Introduce a New style of thinking; Combat Marksmanship Program, Extra Marksmanship Program, Civilian School instruction to the Military. Then new programs were developed internally with special names, which has now become Tables 1-2-3 & 4, 1 & 2 are required annual trianing, Tables 3 & 4 are required before going into combat by most units now, the Army has developed similar shooting packages. Each Unit likes to develop thier own shooting package tailored to what they feel is best... which technically right, but we do it.
So now we've effectively retrained our way of thinking to make the most out of the 5.56mm round. Weapons have started to change from the A2/A4 to the M4's, Optics have improved and are more widespread. Training was the biggest issue, not the round have lead the way to "easier kills". Not to mention the Designated Marksman's rifles being spread through out the operateing forces.
Now the question is, if you equiped these finely trained men, who no longer complain as much about the 5.56mm, with 6.8mm or .308's, what would the out come be? Would we put more bodies down, or would we then be haveing issues with limited magazine capacity and recoil?