Does anyone know if the stock has any recoil-absorbing properties?  

gatnerd said:

Notable for 2 3 reasons.

3.  First time it's been seen used by a female soldier.  

nincomp said:

Does anyone know if the stock has any recoil-absorbing properties

Not thats been revealed; probably not as the rifle would be pogo sticking under rapid fire.

Those sort of spring / hydraulic buffers in the stock seem better suited to grenade launchers and shotguns.

An older video from Ian that I'm surprised I missed that gives a very nice deep dive and field strip of the NGSW, and also explains how its able to handle 80kpsi.

YouTube

SIG M5 Spear Deep Dive: Is This a Good US Army Rifle?

https://utreon.com/c/forgottenweapons/http://www.patreon.com/ForgottenWeaponshttp://www.floatplane.com/channel/ForgottenWeaponsCool Forgotten Weapons merch! ...

80kpsi discussion begins 23:42.

How it works:

1. Gas port / piston hole placement and size determines ammount of gas force sent to the bolt, not the pressure of the cartridge. So port is simply tailored for 80kpsi.

2. Barrel is a thicker profile, especially around the chamber, but not unusually thick. Looks similar to the SOCOM profile of the M4A1 but scaled up to AR10.

3. Bolt geometry. This was the most interesting to me. 

I assumed the bolt would be massive, but its actually a bit smaller then the bolt on the AR10:

However the length of the lugs is ~2x longer, which Ian believes is more important for the bolt strength vis a vis the higher pressure:

Came across this:

How is this not better than the M4?

It's just a meme I came across while looking for more NGSW content. 

Design wise, the only real downside is weight. Otherwise it's basically an ambidextrous, folding stock piston AR.

Excellent history, overview, and insights into the NGSW program:

https://www.americanrifleman.org/content/return-of-the-rifleman-the-next-generation-squad-weapons-program/

Some excerpts:

The Army’s ballistic needs required a cartridge larger than the 5.56 NATO and a weapon larger than an M4 to fire it. A loaded XM5 with the XM157 optic will weigh about 3 lbs., 4 ozs., more than a loaded M4A1 with an M68 optic. With a full combat load, the XM250 outweighs the M249 by about 3 lbs., 8 ozs., while carrying 200 fewer rounds.

...

According to the Army, the XM5 basic combat load is seven, 20-round magazines, which weighs 9 lbs., 13 ozs., in total.

..

For the XM250, the basic combat load is four 100-round pouches at 27 lbs., 1 oz.

...

For comparison, the M4 carbine combat load, which is seven 30-round magazines, weighs 7 lbs., 6 ozs., and the M249 combat load is three 200-round pouches weighing 20 lbs., 14 ozs., in total.

...

This would result in a real-world total combat weight of 21 lbs. for the XM5 and 43 lbs., 6 ozs., for the XM250, versus 15 lbs., 10 ozs., for the M4 and 39 lbs., 14 ozs., for the M249.

Also some looks at the EPR; not sure if factory or prototype:

Weight estimation for 6.8x51:

Pretty well-written article, although IMO this weight comparison is flawed and rather unfair:

"A loaded XM5 with the XM157 optic will weigh about 3 lbs., 4 ozs., more than a loaded M4A1 with an M68 optic."

An apples-to-apples comparison to M4A1 with suppressor, polymer mag, and XM157 optic (or at least a LPVO) would show less weight difference.

stancrist said:

Pretty well-written article, although IMO this weight comparison is flawed and rather unfair

I think it's both a fair and unfair comparison. 

Unfair, for as you say the weight is based on the NGSW with its big FCU and suppressor vs M4 with a red dot and IR laser, no suppressor. 

Yet the comparison is fair if we view the systems by their 'fighting weights' as the two systems are actually deployed by the US Army.

For the last 20 years, the basic M4 loadout for the Army in Iraq and Afghanistan was the M4 with either a Aimpoint or ACOG + IR laser, no suppressor. That represents its 'fighting weight'.

If NGSW is intended to always be suppressed and use a special FCU, then thats its 'fighting weight.' 

And so an Army soldier transitioning from a M4+M68+IR to NGSW+FCU+Suppressor will notice a +3lb weight gain in what they're carrying.