stancrist said:

AFAIK, there is nothing which says the GP bullet necessarily weighs 135 grains.

Absolutely.

The only clues we have are that:

• the bullet in the picture should be lighter than 135 gr with the current EPR construction, but this weight could probably be achieved using the original bismuth-core EPR,
• at least 2 competitors (True Velocity and PCP tactical) used outsourced 135 - 136 gr solid copper bullets for their in-house development phase.

EmericD said:

at least 2 competitors (True Velocity and PCP tactical) used outsourced 135 - 136 gr solid copper bullets for their in-house development phase

We also have Soldier Systems initial reporting on the SIG's specs, which quoted 135gr @ 2850fps 13", 3000fps 16". So thats our 3rd indication of 135gr being relevant.

The Cobalt / MARS offering was a 140gr @ 3200fps, which as far a I know is the exception. But that could be simply the round they showed to a gun mag after they were not selected. 

https://www.thefirearmblog.com/blog/2022/04/26/us-army-discusses-ngsw/

Most interesting line:

Interestingly, Brigadier General Boruff also noted that his team was not ‘allowed’ to work with any of the submitting vendors until after the downselect. He said “the exciting point for us is that we can now work with SIG Sauer, we can refine some of the pressures in the weapon which will enhance the ammunition as we move forward.” As the US Army builds up its ammunition manufacturing capability Brigadier General Boruff explained that weapons and ammunition refinement will continue.

Which means what, exactly?  

Thats the question. More pressure? Less? We'll have to see. 

"as we move forward"

im assuming this means the army will use the spear as a platform like the m4...? will they field it sooner or after years of fine tuning?

 

I honestly think that projects like NGSW should be done in at least two phases.  The goals in this case were beyond current feasibility, so the vendors had to guess which compromises would be preferred.  Although we don't yet know the initial "requirements" in the NGSW RFP, we have seen reports that those for the velocity and weight reduction were reduced after the fact.   It seems that the initial downselect eliminated who guessed wrong and decided to meet velocity "requirements".  They submitted  larger-diameter conventional cartridges at "normal" pressures (6.8 short mag and 6.8 Sherwood).   The eventual winner chose unusually high pressure cartridge requiring a relatively expensive case, the same size as 7.62x51 and with minimal weight savings. 

Competitions where none of the competitors can meet the aspirational goals lead to a situation of : "We would have proposed something different if we had only known the compromises you woulsd prefer." A second round of competition between TV and SIG would have allowed both companies to home in on functional improvements.  I would guess that TV would raise chamber pressure, permitting either a shorter version of what was submitted or non-bullpup versions.  They would probably submit a belt-fed LMG.   I have less of an idea of that SIG would change, but possibly felt-recoil reduction of its rifle.  

Being an engineer, I also think that contracts like this should cover development expenses so that best ideas from all the competitors can be combined.   In a competition like this, seldom does one competitor have ALL the best ideas.  We may never know if the best compromise was a high-pressure TV cartridge in SIG weapons, for example.  That is, unless TV works on a similar idea to sell to other countries.

nincomp said:

Competitions where none of the competitors can meet the aspirational goals lead to a situation of : "We would have proposed something different if we had only known the compromises you woulsd prefer." A second round of competition between TV and SIG would have allowed both companies to home in on functional improvements.  I would guess that TV would raise chamber pressure, permitting either a shorter version of what was submitted or non-bullpup versions.  They would probably submit a belt-fed LMG.

I don't see any logical reason for those conclusions.

1.  Being chosen for a second round would validate TV's submission of a bullpup NGSW-R and -AR, giving TV no cause to develop non-bullpup versions and/or a belt-fed LMG.

2.  Even if TV somehow concluded that they should switch horses mid-stream, who would design and develop a belt-fed LMG for them?  I doubt either TV or Beretta is able.

stancrist said...

2.  Even if TV somehow concluded that they should switch horses mid-stream, who would design and develop a belt-fed LMG for them?  I doubt either TV or Beretta is able.

Given that the TV round works out of anything that can run 7.62x51mm, FN or Knights Armament could have a go?

gatnerd said:

       EmericD said: at least 2 competitors (True Velocity and PCP tactical) used outsourced 135 - 136 gr solid copper bullets for their in-house development phase

We also have Soldier Systems initial reporting on the SIG's specs, which quoted 135gr @ 2850fps 13", 3000fps 16". So thats our 3rd indication of 135gr being relevant.

I agree that it is reasonable to conclude that the 135gr weight of the surrogate bullets is relevant.  However, that information does not necessarily indicate that the steel-tip GP projectile weighs ~135 grains.

Considering the expected cost of the tungsten-tip SP armor-piercing bullet, I think it's far more likely that all of those 135gr surrogate bullets duplicate the weight of the SP round, not that of the GP projectile.

The certainty in this forum that the pictured GP bullet weighs only circa 120 grains would seem to support that idea.