Sig Sauer Wins NGSW (XM5): They Understood the Assignment

Get ready for some serious armchair quarterbacking.

The US Army has made it’s choice on the Next Gen Weapon System (NGSW), and that choice was the Sig Sauer entry, which shall be designated the XM5 until it hits operational status. It’s a modification of their MCX-SPEAR platform, chambered in something that is either exactly or strongly similar to the 277 Sig Fury cartridge that I wrote about a while back.

This video explores in some detail the infantry rifle portion of the project; it doesn’t talk much about the automatic rifle.

One thing that I got wrong, I think, on the 277 Sig Fury is that I spec’d it out as delivering 3,000 fps from a 16″ barrel; the actual rifle seems to come in at 13 or 13.5″ long (330 to 343mm). That’s a very, very short barrel … but note that the current M4 has a 14.5″ barrel, so the new one isn’t that different from the current model, but hits a lot harder.

I note that by extending the barrel to 20″, the required pressure drops down to 70,000 psi, and you can get down to conventional magnum pressures (65,000 psi or so, which, I note, is the actual pressure of the 6.8TVM entry) at that barrel length without mucking around too bad with powder burn. If that sounds a lot like the competing True Velocity and RM277 bullpup rifle strategy, you’re not wrong. More on that later, but “we’re going to deliver the target velocity out of a short barrel” is something that, if you know about it ahead of time (and they did), you “just” design for. Thus the higher pressure (and probably a lot of tuning of the burn profile of the powder in the bullet).

The video hits the common operating points with the M4 really hard, and when industry observers talk about “conservative” design, they really meant it, and the impression the video gives me is one similaar to many large-scale manufacturing presentations: They retained as much back-compatibility as possible. The manual of arms is more or less the same, from charging handle to grip flavor to the overall pattern of the weapon, which borrows extensively from the AR10 and AR15 family of platforms. Grips, forends, attachment points, folding stocks and compressible butt-stocks. Gas piston rather than direct impingement. They mention the rear charging handle and a non-reciprocating side-charge as well, the fact that you can use the same magazines (any .308/7.62 mag will take the 6.8x51mm), the position of various levers, and a lot of the same manufacturing equipment for the ammunition. For a military with a rather stupendous logistics train, not having to recapitalize the firearms ecosystem is probably a comforting feeling. “This was your old rifle; the new one is like the old one, but better” is not a bad story to  tell the US Military and its troops (especially if it turns out to be true). While it’s not the clean-sheet design that I might have hoped for, one look at (say) the L85 rollout for the British army before Heckler and Koch were retained to make the darn thing work right shows the potential shortcomings of said clean-sheet design. It’s likely going to be rather substantially heavier than the M4 and the recoil could be substantial.

The competitor – the RM277 weapon family – was an incredibly compelling blend of new technology and handling. I’m totally biased in favor of anything bullpup (I love how they feel, shoot, and the handiness of them is so neatly into the requirements of both a service rifle and something CQB capable that it’s not surprising that at least one entry tried this route). So there’s that. Based on prior photos, I calculated that the barrel would be roughly 20″ long based on pixel-matching measurements, and the True Velocity “Genesis” rifle that will be the civilian version of the bid claims a 19″ barrel (I was so close!) in a sub-30″ weapon (my prior post had it as about 33.5″). There was really a lot to like about it. Including the reciprocating barrel (obvious in all the videos of the weapon firing) to tame the recoil impulse, longer barrel, and of course the polymer ammunition. And bullpup! More seriously, it also operated at 65,000 psi instead of the 277 SIG Fury’s 80,000 psi. So lower potential for barrel wear (though if you’re designing a barrel for 80,000 psi nominal operating pressure, presumably you also design the hardening/coating of said barrel to take that pressure with reasonable service life).

There were – in my mind – two problems with the True Velocity/Lone Star Future Weapons/Beretta/General Dynamics entry that were probably the death knell for selection.

The first is, to my mind, the most egregious: The program was to select a family of rifles. An infantry rifle and an automatic rifle, basically a replacement for the M4/M249. The M249 Squad Automatic Weapon is a belt-fed support weapon.

Belt. Fed. 200-round belts. Linkable into “crunch all you want, we’ll make more.”

The NGSW-AR requirements were to engage pinpoint targets at up to 600m, and suppression to 1,200m. You’re just not going to suppress much of anything limited to a 20-30 round box magazine, and I never, not once, saw the True Velocity offering depicted with a manufacturing trajectory that wound up with a high-capacity program. Belt, drum, uber-box, anything.

I did recently see this image, though:

This looks like a belt-fed version of the 6.8TVCM. So it seems to be doable…but they didn’t do it. Basically, the team delivered a super-updated M1918 Browning Automatic Rifle.

I remember back in graduate school, I had to basically warn a student that while their final design project met some of the requirements, it deliberately ignored others, perhaps the most important ones. If they turned it in, they would fail.

I don’t think you can submit a game-changing rifle family full of new tech into an Army that has been fighting wars actively for the last two decades and say “trust us, we’ll eventually deliver the requirement for a support weapon.” Or even worse: “Dang it, just have your guys change mags ever 4-6 bursts!”

Even if the rifle(s) were technically superior to the Sig entries (which may or may not be the case), the lack of any option to deliver 100 to 200 rounds of ready ammunition into the mouth of a support weapon represented a failure to comply with the basic program requirements for half of the design request, at least from my seat up in the nosebleed section. It is, of course, possible that all of these things were being contemplated, planned, and even executed. But if you’re going to have your rifle be a belt-fed, show it in the press photos (see the Sig image above!).

Combine that with an historical reluctance for the US Military to embrace the different manual of arms for a bullpup rifle, and I think one runs into severe headwinds. (And the Israelis also vary between the AR-style and the Tavor bullpup and the Chinese moved away from the QBZ-95 bullpup to the QBZ-191, so this isn’t just the AR-mafia coming to this conclusion. Or perhaps it is, but the mafia is Just That Big. But “ergonomics” has been a stated limit for bullpup style rifles for a long, long time now.)

This is despite the fact that the 6.8TVM cartridge offers something like a 30% weight savings over conventional brass-cased ammunition (so 10 magazines full of cartridges instead of 7 for roughly the same weight) AND the insulating polymer case actually reduces barrel heating, as less heat goes through the plastic container than the metal case. That’s a huge advantage in an infantry rifle (oh, sure…you notionally could just lower the soldier’s carried weight, but that hardly ever happens in practice. “Oh, we shaved a few pounds of ammo! More ammo! More batteries! More of other things! The grunts’ knees aren’t breaking yet!”) and the Army let it go.

In short, and to revert to the title and a really over-used meme/song: Sig understood the assignment.

I do wish things had been different, because I do love me my bullpups and historically I feel it’s better to start with a longer barrel (so you can cut it down if needed). If the True Velocity case can be engineered to handle even more than the currently-available 65,000 psi, that give you the opportunity to upgrade the weapon as you go. The bullpup configuration allows an even longer barrel if desired –  the current M4 with the stock collapsed is something like 34.5″ long, which means the 29.5″ long Genesis rifle could mount a 24″ barrel, with the commensurate increase in velocity and range, and still be as handy as the current M4 in its smaller configuration. That’s a nice Designated Marksman option.

But they were not different, and hopefully we’ll see a smooth and trouble-free roll-out of what promises to be a very interesting new weapon system, even if it’s not as aesthetically pleasing to me as I’d like.