Master Review: Sig Sauer Next Generation Squad Weapon (MCX Spear)

Sig Sauer has been awarded the contract to provide the US Army with the next generation of rifles and machine guns. They did a truly outstanding job engineering the Sig Sauer Next Generation Squad Weapon. This article is going to cover the civilian variant, called the MCX Spear, as well as the amazing new hybrid ammunition created for these weapon systems. We’ll go over its specs, shooting impressions, and the all the relevant details. Keep reading for more.

If you’ve read any of my other master reviews, like the Sig Rattler, or the HK VP9, you’ll know that these reviews are a compilation of all the best information on the firearms. I take the time to comb the internet for all the relevant info so you don’t have to. You don’t have to thank me for my service.

The U.S. Army has officially chosen the Sig Sauer MCX Spear as the winner of their Next Generation Squad Weapon contract. The evaluation effort put all the submissions through, literally years of numerous technical tests, to determine which NGSW system was the best. Obviously, the Sig Sauer provided the best option. As you’ll see, this rifle is a leap forward in battle rifle technology. Here’s a quick overview of the weapon.


Sig Sauer NGSW (MCX Spear) Overview

  • Winner of NGSW Program
  • To be Fielded to Army Close Combat Force
  • Piston Driven Weapon System
  • Large Frame Version of the MCX Carbine
  • MCX Spear Ships with Suppressor for Sound and Flash Reduction
  • Similar Solider Touch Points and Overall Operation to M4 Carbine
  • Utilizes new 6.8x51mm Sig Fury Hybrid Ammunition Developing (80,000 PSI Chamber Pressure)
  • Expected Barrel Performance of 12,000 Rounds Before Replacement
  • The Rifle Weighs 8.4 pounds
  • Vortex Will Provide the Optics for the Rifle

The Next Generation Squad Weapon Program

The M4 carbine (M4a1 Carbine) has been around for decades, and is deserving of our respect. However, it’s past time for an upgrade, as the carbine is outdated. Sig Sauer has provided significant capability improvements with the MCX Spear, (in military parlance the XM5 Rifle).

The real impetus for developing these new weapons was a need for improved range, and lethality against armored threats. You can purchase level 4 body armor plates for a couple of hundred dollars that will stop nearly any rifle round. The Pentagon hasn’t ignored this fact. They were adamant that they needed more lethal ammunition.

This causes a real problem when developing a new rifle system. If you read my previous article, which analyzed 133 Military Firefights, the authors of that research determined that close quarters battle was a requirement of every battlefield, as were longer range engagements.

Photo Courtesy of Sig Sauer

Similarly, the ever increasing weight of military equipment posses a real hazard to the troops who have to carry it. In my article, in which I review the lightest tactical equipment available, I covered some research that demonstrates that adding only 15 more pounds to each Marine in a Marine Corps squad, could result in increased casualties. This was true even when that weight was for better armor!

The Next Generation Squad Weapon needed to be light weight, as well as very controllable at all distances, from hundred of meters, to point blank range. As you’ll see, Sig Sauer created a great weapon system that checked all of those boxes. First, we’re going to talk about the MCX Spear.


Join the Email List

If you like fitness, shooting, and firearms, then  click here to join the Tier Three Team. It’s totally free, and over seven thousand members get the latest articles sent directly to their inbox.


NGSW Rifle the Sig Sauer MCX Spear

The Next Generation Squad Weapon program rifle, or the XM5, is currently sold commercially by Sig Sauer as the MCX Spear. They’ve begun to sell their first production run. It features the exact same build as the military version, except you don’t get the automatic rifle variant. I know some of you are bummed out, but a select fire version would require a second mortgage for all the .277 Sig FURY ammo.

The military is going to be adopting the 6.8x51mm cartridge, which is labeled by Sig as the .277 Sig FURY. Because this round is similarly sized to the 7.62x51mm (.308 case), it can easily shoot .308 or 6.5 Creedmoor rounds with a simple barrel swap. I expect Sig to release several variants of this rifle, in different calibers, for those that don’t want to buy a million barrels. Next, let’s go over the rifles specs.

Sig Sauer MCX Spear NGSW Winner
Photo Courtesy of Sig Sauer

MCX Spear Specifications

The Sig Sauer MCX is a piston driven AR10 sized rifle. Because of the MCX style system, the Spear doesn’t rely on a traditional buffer tube, and spring system. This allows the butt stock to be folded. The size of the firearm depends almost completely on the size of the ammunition that it is shooting.

The ammo is called the 277 SIG FURY, or formally 6.8×51 mm. It isn’t the same as other 6.8mm rounds, like the 6.8 SPC. This new ammunition has a hybrid metallic case, that develops extremely high pressures. We’ll talk about this is a little further on. The biggest take way is that this rifle has to be bigger because it shoots a similar size cartridge to 7.62mm ammunition. Check out the MCX Spear specs below.


Sig Sauer MCX Spear Specifications

Courtesy of Sig Sauer

I can tell you that Sig did a good job of making a very capable rifle at a reasonable weight; however, I think this new platform does have a very serious drawback for the warfighter. The size of the round, and the 20 round magazine capacity will cause a drastic increase in weight that must be carried.

A standard combat loadout for infantry forces is 6×30 round magazines, or roughly 180 rounds. This combat load can be carried using three double magazine pouches, or 5 single mag pouches, with one mag in the rifle. This is fairly easy to fit on a plate carrier.

When you move to larger 20 round magazines, you’ll find it’s much more difficult to carry, especially considering that you need to carry 9 magazines. The loaded weight for 9 magazines of 277 Sig FURY is about 13.5 pounds. This is compared to 6 loaded 5.56 PMAGS, which comes in at 6.5 pounds for a combat load. Using our our data from the lightweight gear article, this increase in ammo weight and overall soldier’s load could cause a 4% increase in casualties.

MCX Spear Ammunition .277 Sig FURY (6.8x51mm)

After doing my research on this topic, I’ve discovered that the real story is the new hybrid case ammunition. This round develops much higher chamber pressures than conventional rounds. The 5.56 mm NATO round is limited to 66,000 PSI of pressure. This 6.8 round develops 80,000 PSI.

This allows the round to develop much more velocity, even out of the rifles 13 inch barrel. Moreover, this increase in velocity also translates to more energy on target, at every range. Currently the military is planning to use 135, and 150 grain projectiles. Recall that the standard 5.56 round is only 62 grains. Quite the change. Let’s take a look at some ballistic charts to see just how big this difference is.

MCX Spear Ballistics and Stopping Power

A big reason the United States Army wanted a new round was because they will need to defeat enemy armor, at any range. This requires more energy, and velocity. It doesn’t hurt that large high velocity rounds are better at extended ranges. Take a look at the charts below.


Sig 277 Fury Velocity Chart
277 Sig Fury Energy Chart

I want to be clear about this data. Much of the velocity and energy data for this round is out of a 16 inch barrel, which is longer than the 13 inch barrel the MCX Spear ships with. I’ve done some basic math to extrapolate what the velocity should be out of the 13 inch barrel. Expect this data to be fairly close, but not perfect.

You can see that the extreme chamber pressure this round develops translates into high projectile velocity, and energy values. To put this into into perspective, a 55 grain 5.56mm round out of a 13 inch barrel, is around 2700 ft/s. The 277 Sig FURY round is triple the weight, and only gives up about 100 ft/s in velocity. I don’t see any reason why the effective range of this rifle couldn’t extend to 1000m, where the round is likely still super sonic.

The energy values are similarly impressive. A 5.56mm round, at the muzzle, is about 1280 ft/lbs of energy. At 500 yds, the 5.56 out of a longer barrel, is only 339 ft/lbs. You can see, from the estimated chart above, that the 277 Sig FURY retains more energy, at all ranges. In fact, at 500 yards it retains almost the same energy as the 5.56mm round has at the muzzle. These are great numbers for small arms. Next, let’s talk about some of the shooting impressions.

MCX Spear Shooting Impressions

Having watched entirely too much video of various folks shooting the MCX Spear, I can say that it performs about how you would expect. It certainly has more recoil than a 5.56 rifle, but this recoil is mitigated by the sound suppressor and the adjustable gas system. If you watch the video below, you’ll see that it’s somewhat controllable on full auto. However, there won’t be any long strings of fire here!

There are a couple of key details that I think will definitely increase user satisfaction with the gun. The first is the non reciprocating side charging handle. These types of charging handles are ideal for clearing malfunctions and loading. Rest assured it still has a traditional charging handle for those that can’t learn new things, right Gerald!

It’s also important that the gas system allows for increased gas under adverse conditions. I can tell you that the infantry will certainly find those conditions. I can’t tell you how many times I’ve seen Marines fall into mud or snow and completely gum up their weapons. This is annoying in training, but life threatening in combat.

MCX Spear Optics

All the photos you’ve seen so far, feature the MCX Spear with a Sig low powered variable optic LPVO. That’s not how soliders will use this system. Vortex Optics has been awarded the contract for the Next Generation Squad Weapons Fire Control System.

This 1-8x variable magnification optic is smart, and it incorporates several features that are likely to increase first round impacts. It incorporates a laser rangefinder, atmospheric sensor suite, and a ballistic calculator into the unit. This data is incorporated into the reticle. It allows you to hold the crosshairs on the target without needing to aim off, or dial on the turrets. In effect the sight does much of the aiming for you.

The box on top of the optical tube is where the lasers are housed. They also incorporate visible and IR lasers into the unit, which effectively eliminates the need to have a separate unit like a PEQ15 or DBAL. Vortex is not talking about the weight, but I would estimate this is close to 2 lbs with everything pictured.

Provided that the unit is rugged, and the ballistic calculations are accurate, this might be a great piece of gear. The number one cause of inaccurate rifle fire is poor range estimation and wind holds. It looks like this sight is trying to tackle those issues head on.

I do wonder if the infrared aiming laser might be a problem when facing folks that have night vision equipment. It wouldn’t do to effectively flash a light, letting the enemy know where you are. It’s a bold step Cotton let’s see how that plays out. I’m sure there’s a way around this, but the DOD is keeping the details hush hush.

This certainly is a sweet set up, but the rifle alone retails for $7999. I’m guessing this optical system is at least as expensive. The question remains, do you really need to spend more than $15,000 for this kind of capability? The answer is no, and I’ll show you a great option for a civilian battle rifle.

The POF Revolution

If you’re looking for a light weight, piston driven battle rifle, then you really only have one place to turn to, Patriot Ordinance Factory (POF). POF Makes some great rifles. In fact, I use their POF Renegade as my bump in the night gun, and have really enjoyed the high quality and thoughtful engineering they put into their guns.

The POF Revolution is a 308 or 6.5 Creedmoor rifle that has been shoe horned into an AR15 sized package. It is not an AR10. It comes in a variety of barrel lengths, from 12.5in all the way to 20 inches. If you compare the 12.5 inch 308 pistol variant to the Sig Spear, you’ll see that the Revolution only weighs 6.5 pounds. If you add a suppressor, that brings it to around 7.5 pounds. This is still lighter than the MCX. Check this video out.

Because POF doesn’t use incredibly high pressured 277 FURY rounds, you might want to opt for the 16 inch variant. I would recommend a good low powered variable optic, like this 1-8x Trijicon Creedo. If you purchase a rifle, suppressor, and optic with mount, you’re looking at around $4900 for the same capability. If you want to save even more, you can go with the non piston variant called the POF Rogue which is about $500 less.

Final Thoughts

I can tell you that I’m excited to see how the new rifle performs. I’m even more excited to see all the civilian variants that Sig will be producing. There are already some hints that they’ll producing a MCX Raptor which is a scaled down Spear, similar to the Sig Sauer Rattler.

I’d also bet that other companies will start to make rifles that take advantage of the ballistics of the 277 Sig FURY. The future sure is looking bright, as long as you don’t look at your credit score! If you have any questions or comment put them below!


Any links to Palmetto State Armory, Brownells, or Sportsman Guide, are affiliate links. That means if you click on them and purchase, they pay us a referral fee. It costs you nothing, and helps keep the lights on here. We appreciate the support.

Source link: https://www.tierthreetactical.com/master-review-sig-sauer-next-generation-squad-weapon-mcx-spear/ by Jake at www.tierthreetactical.com