Luckily for me I was young enough for the issues to have been resolved with the M16 before I got into the fray. The 5.56 has in my opinion within current technology reached the end of it ability to be improved.Sigs new military round looks badass. 6.8x51. Necked down 308 to .277. Had to put a steel sleeve around the head for the 80000 psi it generates. 135 gr at over 3000 fps. Basic short .270 . They finally figured out that the 556 is a pc of crap. Only took 54000 dead GI's in Nam to get it right. "we the people" Rob
I've carried under field conditions the M2 Carbine in M1A1 configuration, the M14, 16A1, 16A2 CAR15 and several bolt rifles in different chamberings.
I'm pessimistic about the new cartridge and the rifle under general combat conditions. As a special designated rifleman concept it has its appeal.