poliorcetes said:

Possibly it was answered quite a long time ago but... why 6.8x51 case is not all steel like Russian cases in order to save weight and be much more cheap to build?

I don't know if "all steel" cases will be cheaper, I suspect that the process to build the 2-parts case makes the material cost less important.

As for the reasons that SIG didn't proposed an all steel case, first steel is not a really good material for the case body. You can make a decent all steel case, but it's not an everyday business among Western manufacturers, the process is very special and SIG probably didn't have enough time to develop it during the NGSW competition.

Second, the "high pressure" NGSW cartridge is still under development, as the US Army really want a true lightweight round, so maybe the final iteration will be very different from the things we already saw.

Russians playing with bimetal 'import subsituted' cases for their ELR sniper rifles. They say bimetal manufacturing makes for much better tolerances particularly in the neck area  and is this case comparable to cost of imported brass.

But of course with large sniper cases made in low numbers  , costs are on different plain .

1. Even if steel base + washer + brass body is not so expensive, it also would need a good number of resources in order to make it viable at the manufacturing line. Would such resources be more at hand rather than go to steel only?

2. Is there any clear indication than bimetallic .277 is not going to be the final case for the cartridge? Are there any hints of a less powerful GP variant? 

3. I would assume that any polymer case should reduce slightly the propellant volume. Maybe a less long GP round would compensate it, or maybe it also would pointed out to the direction of reducing muzzle energy since COAL is already be written on stone

Reportedly, some Rangers already getting NGSW:

https://www.reddit.com/r/MilitaryPorn/comments/10a2g7j/rangers_of_the_4th_ranger_training_battalion/

One Reddit poster said the photo is from a "Rangers in Action" demonstration at Ranger School graduation.

Both soldiers are posed taking a knee, likely participating in a skit like https://youtu.be/fDw-aYTBghc?t=1545

Interestingly, the Ranger School instructor with XM5 does not appear to have any 6.8 mags or mag pouches.

I would expect that the new rifle will be in limited issue to some units to take to the field and shake the bugs out of the design. 

Better to have troops use it in training and see what problems there are than issue it to troops in the middle of a war. Seems like the U.S. did that in the 1960s.

17thfabn said:

Better to have troops use it in training and see what problems there are than issue it to troops in the middle of a war. Seems like the U.S. did that in the 1960s

Quite true, it would be good to find out the kinks now rather than waiting for paratroopers defending Taiwan to discover them. 

stancrist said:

Interestingly, the Ranger School instructor with XM5 does not appear to have any 6.8 mags or mag pouches.

The second Ranger is so out of focus, I didn't notice before that he not only has no ammo belt containers for his XM250, but the weapon also curiously lacks an XM157 FCS...

Good catch. I think it being a promo photo is the likely explanation then.

Your comment reminded me of a statement made by one of the soldiers from the battle of Mogadishu.  The rescue convoy did not provide enough vehicles to carry all of them out, so some soldiers who were out of ammo had to run behind the vehicles while trying to look fierce and indestructible.  It sounds a little fishy to me (no ammo), but makes a great story.