Tactical Life posts that the military is changing to the 6.8 in SAW and M4

[stanc]

None of this "6.8" news should be considered a continuation of the Great Intermediate Cartridge Wars.

First of all, as LR and others have noted, this 6.8 does NOT mean the 6.8 SPC.

Second, the 6.5 Grendel has already won, in the sense that any new cartridge will NOT use a stubby, low BC bullet like the 6.8 SPC, but will use a sleek, high BC bullet like the 6.5 Grendel.

Hello?!? That's what we've been telling them since 2003. . . .

It is the CONCEPT that matters for our military, not the caliber.

The Grendel concept was a sleek, high-BC bullet at low-moderate velocity.

The Army's concept is a sleek, high-BC bullet at EXTREMELY high velocity.

HUGE difference. More like 6.5-300 Weatherby Magnum than 6.5 Grendel.

Having said that, I don't know why they wouldn't uses the 6.5mm caliber, which is the perfect compromise — splitting the difference between .22 and .30 cals. Any research department that seriously thinks there is a meaningful difference between 6.5 and 6.8 bullets of the same form factor is fooling themselves.

There are other factors to consider. For one, with bullets of equal weight, 6.8mm permits higher muzzle velocity (than 6.5mm) at the same operating pressure.