@ Raz - get-um while congress is on vacation!
Not a bad deal these days, at Target Sports USA
Federal 5.56mm XM855 NATO 62 Grain FMJ 420 rds on Stripper Clips in Ammo Can
Special $210.00
FREE SHIPPING INCLUDED
My rifle has a slow twist (1:9), so the higher price for the heavier bullet doesn't buy me anything. I stock up when I get the 55gr at around $0.40@. My next such rifle will have a faster twist and a longer barrel.
Just re-barrel it.
But then I don't have an excuse to buy another gun.
But you don't have the money for a new AR anyway so just what difference does it make at this time?
I thought "hunting rifle" was next on the list... not that you couldn't hunt with another AR. Does he already have a .308? 
Oh, and I'm not terribly interested in a .308.
You were not interested in a full size .40 either so you bought two.
I didn't say I wasn't interested in it, only that I didn't NEED it.
I don't need a .308, but I'm also not particularly interested in that cartridge.