https://twitter.com/JakOSpades/status/1522505470598168577?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1522505470598168577%7Ctwgr%5E%7Ctwcon%5Es1_&ref_url=

design of sig lmg to xm250 has slight differences. 

I really wonder how much long term durability this gun is going to have. The 6.8NGSW is substantially hotter than 7.62NATO, and the XM250 is extremely light weight. At this point I wouldn't be surprised if the design picks up several lbs in the next few years as it transitions to adoption then A1/A2/etc forms.

Apsyda said:

At this point I wouldn't be surprised if the design picks up several lbs in the next few years as it transitions to adoption then A1/A2/etc forms.

The Sig MCX 5.56 started off ~2015 as a beautifully balanced 6lb rifle. I held it when it was debuted at SHOT and though 'wowza!'

Well it got taken off the market, multiple versions later the 'MCX Virtus Patrol' is now a hulking 7.9lbs....it went from the lightest piston 5.56 in the world to one of the heaviest 5.56 rifles in the world. 

So I could absolutely see the NGSW's gaining weight over time. 

The original virtus was In many ways the inspiration for my current AR pistol build.

So much so that my 11.5" bbl foxtrot Mike bufferless AR is actually going to wind up sporting a sig folding buffer tube knuckle (the sig folding tube to picatinny knuckle is gorgeous and gas very nice positive lockup) mated to a tailhook mod2 assembly.

Picked up a PA dot and magnifier which sit on a lower 1/3 cowitness riser and has the magnifier folding left along with the brace.

Unlike virtus it's a DI unit but it took a lot of cues from what sig did there. It should weigh somewhere between current virus weight and original virtus weight all up and my ammo of choice will fragment out to 300 meters from an 11.5" tube.

We desperately need to get back to light handy guns if for no other reason than so we can put 3 pounds of shit on them and ONLY have them weigh as much as a loaded Garand all up.

https://www.youtube.com/watch?v=GEf3ZlUkOCg

garand thumb vid yay

6.8 if...... it ends up in widespread U.S. service would be a third rifle cartridge after 7.62 and 5.56 for NATO members. 

At this time NATO members can use 5.56 or 7.62. They are not forced to choose. Even if 6.8 is adopted by the U.S. , the U.S. will still continue to have weapons in 5.56 and 7.62.

You seem to be missing the point.  Both 7.62 and 5.56 were "forced" (by the US) upon NATO.

NATO adopted 7.62 (over .280) due to US insistence upon a full-power, .30 caliber cartridge.

When 5.56 became the US standard rifle caliber, it in effect became a de facto NATO caliber.

The same thing will almost certainly happen if the 6.8 is fielded by the US Army as planned.