Doctrine and why the Grendel has an uphill battle.

[stanc]

I just weighed a 25rd Grendel magazine with 25 Federal 120gr HPBT Match Load cartridges on it. Came to 1lb 5.4oz / .60kg
30rd Magpul PMAG with 69gr SMK HPBT load is 1lb 2oz /.51kg

7 x 30rd .223 Rem 69gr = 3.57kg or 7.87lbs for 210rds
7 x 25rd 6.5 Grendel 120gr = 4.2kg or 9.2lbs for 175rds

I think that weight could be cut to 8.7 lbs if a P-Mag were to be developed, and filled with a 105gr EPR load. Of course, that'd also require development of a "Six5" receiver.

As far as mags go, it changed everything from where we were able to carry double M4 pouches comfortably across the chest, to now where single shingles are really the only practical way to be able to stay as low-profile as possible. Negotiating in and out of vehicles, window frames, breech points, tight confines, climbing walls, ladders, and rubble present serious challenges even for units with PT standards that crush the regular Army lacking standards of physical fitness.

This is why I quickly started to see the 6.5 Grendel as something that should be replacing 7.62 NATO, not 5.56 NATO. A 6.5 Grendel/5.56 NATO weapons mix would be a breath of fresh air for Joe, who is laden with a lot of squeeze for little juice with 7.62 NATO. We need to get the 5.56 NATO systems weighing less, like the originals...

6.5 Grendel DMR/CSASS/LMG makes a lot of sense.

Indeed. But, I wonder if we'll ever see a belt-fed Grendel LMG, when nobody has yet even made a mag-fed Grendel IAR.

Smaller 5.56 carbines

Only way to make 'em smaller is to shorten the barrel. At best, that'd cut 4 inches from length, and maybe 4 ounces from weight. Worth the reduction in range, terminal effects?

That Colt MARS or the KAC PDW would be great really for a lot of people.

Yeah. I don't see the military going for three rifle calibers in the squad, though.