Having a guy who worked for me on the Army's board I have had a lot of discussions with him over many, many years. I have spent hours on the ballistic tables, this is a good one:
ballisticscalculator.winchester.com/
Having been a Pfc with 14 mo combat time I know well the abilities of the 5.56. Where the 5.56 falters is when you got a mess of hopped up, smoked up, coked up folks intent on killing you. If you don't catch them in the 2 pieplates (head and chest) you will need to try it again and maybe again.
5.56 is the 'double tap' round and for a good reason. VC are not big folks,not at all, but get them stoked up and they are coming in waves you need more stopping power. 5.56 is just not 1 shot 1 kill.
I have also carried the M 14 and let me tell you, that is one heavy weapon and so is a 7.62 basic load.
I see the only rd in the current inventory, that has a history and can be made in quantities able to support a war effort as being the Win .270. Anything else fails at 1 or more criteria to adopt for military use.
It has the stopping power for 1 shot 1 kill, it has the accuracy needed and it in between 7.62 and 5.56.
Granted there is NO shortage of other stuff that would work, most it if you had to buy more than one box you would have order it, just not a stockage item nor is it produced in qty by anyone. Any rd needs to be able to be produced IMMEDIATELY if not sooner by every manuf of ammo in the US. Remember the DHS ordered a BILLION+ rds last year of 5.56.
MRRALEY said its not gonna happen and the reason why is cost effectiveness. He is right and some of the reasons he is right is that for us to move to a different rd requires a new weapon for US AND NATO and guess who will pick up the tab????? Mr Taxpayer USA. It ain't gonna happen. NOT counting the fact that to move to a larger rd would be to ADMIT that the 5.56 should have never been picked to begin with. But the study it was based upon was carry WEIGHT of a combat soldier. Avg weight is 159 lbs, CARRY WEIGHT does NOT include body weight!