Textron Systems NGSW Rifle and LMG

[stanc]

I'm not advocating any specific caliber for the 6.8 NGSW cuz I don't know their performance requirements. Just saying there's no technical reason it can't be 6.5mm.

Of course. It not only can be done, Textron has previously made 6.5mm CT ammo.

Don't really care cuz the fundamental obtuseness of the whole concept annoys me.

It's a conservative, time-proven approach, at least with tanks and infantry fighting vehicles: As armor protection improves, the caliber and power of tank and IFV main guns increase to penetrate the improved armor.

I do have a strong opinion that the NGSW cartridge should have a COAL length no greater than, oh, 2.30" and a case head diameter no greater than, oh, 0.473.

Heh, heh. Those numbers look suspiciously like they were chosen to rule out bullets bigger than 6.5mm. The 6.8mm CT round looks to have a COAL of ~2.60" and diameter of 0.49-0.50".

Set that as a limit to control overall bulk of the cartridge and weapon...

It wouldn't help. If you want to reduce bulk enough to matter, cartridge diameter will have to be much closer to the 0.419" of the 5.56 CT round.

A cartridge diameter of 0.473" would result in magazines as wide and tall as for 7.62 NATO, making 30-round magazines too bulky to be practical.