Having had a little experience with previous versions of the MCX I was excited to see this new variant. Today we will be looking at the Sig Sauer MCX Spear LT, which is an 11.5-inch 5.56 rifle, making it an SBR.
The MCX Spear is a short-stroke piston-operated carbine. It utilizes a spring and buffer system that is housed in the upper portion of the receiver. This has removed the classic AR-type rifle buffer tube where the butt stock was typically attached.
By removing the buffer tube, the role of the Spear can be further adapted to different uses. It can be removed entirely to be used as a “pistol,” or it can be fired with its folding butt stock folded to the side.
The MCX Spear uses many features and familiar parts for AR-15 owners, but I was surprised to see how many differences there were, even with parts that are shared.
The Spear brings with it the incredible adaptability that MCXs are known for and the robust reliability that Sig has rightfully retained. This newest member of the MCX family brings a lighter handguard with improved fasteners to increase rigidity.
Within the handguard is a lighter profile barrel to reduce the weight of the rifle. Inside the rifle’s receiver, there are ambidextrous controls with both safety and bolt-catch on either side of the rifle, and seated in the bottom is Sig’s Flatblade Match Trigger.
I’ve been a little bit of a Sig fan for a few decades, so I was very excited to play with this rifle, and after just a few minutes of handling it, I was hooked.
The quality of the rifle was apparent in every little thing I inspected. Outstanding craftsmanship and perfect lines that all matched up made the rifle incredibly pleasing.
Sig Sauer MCX Spear LT Review
|Barrel Length||11.5 inches|
|Barrel Twist||1-7 inches|
|Overall Length||29.5 inches|
|Muzzle Threads||½-28 TPI|
Pros & Cons
- No buffer tube, fires from folder or without stock
- M Lok compatible
- Short Stroke piston operating system
- Very nice trigger
- Quality controls all around
- Adjustable gas block
- Fully ambidextrous
- Interchangeable barrel capacity
- Multiple calibers (5.56, 300blk, 7.62×39)
- Handsome as the day is long
- Rokset muzzle device
- SBR requires interaction with tyrannical government
On The Range Testing
The MCX Spear was begging to be shot, so I wasted no time.
We took the rifle to a local range which typically, for me, is a non-starter, but today I would make an exception. With an EOtech mounted on top, it was time to cook the tip of the Spear. Today we were shooting some Hornady Black 62 grain FMJ ammunition, which would work great in the MCX’s one in seven twist.
I played with the folding stock for a moment, if only to familiarize myself with it. Pushing on the button with a lifting motion released the dovetail lock of the stock.
With the stock folded off to the side, the rifle supremely compact; only a bullpup could have been much shorter and still maintain a reasonable barrel length.
Shooting the Spear like this would have been easy, but I couldn’t bring myself to shoot it like a pistol, especially after all the legwork of a form four.
With loaded magazines and open range I fired a few rounds, which were quite mild. Small caliber rifles of this size are a joy to shoot. I would have enjoyed it, even more, had Sig not used Rokset on the muzzle brake. Who would buy this thing only to run the factory flash-hider?
To be fair it would be someone with a Sig suppressor that mounts to the brake, but I am not that guy. So I was kind of chapped that it would have taken significantly more effort to remove the flash-hider, so I chose to leave it alone for now.
But I would have loved to shoot it suppressed to see how the rifle worked and if the dual gas settings were acceptable. The eleven-inch barrel definitely needed a flash hider because it launched some serious fireballs.
Shooting the MCS Spear was pleasant as can be, the Sig grip had a very comfortable angle, and the handguard filled the support hand too. The short size of the rifle can, at times, get your support hand a little close to the muzzle, another reason I would have liked to suppress it. The diminutive size of the rifle also made it easy to balance and maneuver.
The MCX Spear isn’t what I’d consider a precision rifle, nor would many folks imagine. That said it was easy to keep shots on target at one hundred yards with no magnification. After fudging with the holographic sight to get a dirty zero, it was easy to keep the shots within an inch or two of the point of aim.
I love the controls of the rifle. The safety was smooth and easily put into either position. The ambidextrous mag releases were right where I expected them and functioned with minimal effort. The ambi bolt-catch made for quick reloads using the trigger finger to send the bolt home after loading a fresh magazine.
It’s also handy for locking the bolt back for inspection or other purposes.
The other finishing touches of the MCX Spear were things like the steel QD sling cups that were fit into the different parts of the rifle. I even disassembled the rifle a bit to see how the piston system and barrel clamp worked.
The handguard was easily removed by two screws and a take-down pin. It slides on a tongue and groove with the monolith top rail of the upper receiver. Underneath, I found the barrel trunnion with two clamping screws; I tipped my hat clean off as I figured out the cunning design Sig had devised.
The two screws work dual purpose as they house a pair of jaws with a tapered face, and they marry an opposite tapered face on the front of the barrel extension. As the screws are tightened, the jaws draw the barrel extension tight into the barrel trunnion block.
Once snugged down, the screws’ second purpose begins to apply clamping force to each side of the split trunnion. Once tight, the barrel extension has been seated tightly against its mating face ensuring accurate head spacing. And the clamping force holds the barrel tight into place.
Besides its intricate manufacturing and design, the MCX Spear LT was just plain handsome! The Coyote finish is a beautiful shade, and the coatings of the other parts were equally immaculate. Every little thing seemed well thought out and executed, and after shooting over a hundred rounds on the first trip, I already loved this rifle.
During the course of several hundred rounds, the MCX Spear LT worked flawlessly. I experienced no malfunctions during testing.
The Spear LT isn’t exactly made for precise shooting, but it is more than accurate enough for the typical duties of a short-barreled rifle.
You may have gathered by now that I am quite happy with this rifle. Everything about it feels good and aesthetically pleasing to my eyes. The coatings, finishes, and every little edge are cleaned up, and it functions as good as it looks.
Buffer Tubeless Action
The dual-spring buffer rides above the bolt carrier in the upper receiver, part of which hangs down to engage the top of the bolt carrier.
By moving the whole recoil operation into the upper receiver, the stock options of the rifle can be changed to near any configuration, or none at all. The already short Spear LT can be further shortened and fired with a folding stock.
The ambidextrous controls of the Spear LT are convenient regardless of your preferred shooting stance. My favorite part is the right-side bolt release, which makes it extremely easy to reload. As you insert a fresh magazine, you can immediately charge the rifle with your trigger finger while your support hand finds its way to the handguard.
With controls on both sides it makes the rifle even easier to operate and obviously much friendlier for left-handed shooters.
The Sig folding buttstock attaches to a vertical pic rail at the back of the lower receiver. The simple construction of the stock appeals to the minimalist in me, with very few things to go wrong.
They even added a small polymer cover where your cheek might touch the stock, which was one of my complaints with the original MCX. Adding a steel sling cup to the back also gives you more sling options.
Adjustable Gas block
As I’d already mentioned, I wasn’t going to try and get the muzzle device off this rifle. Much to my dismay, as one of my favorite things to do is test suppressors on different rifles. I would have loved to see how the two-position gas block would have fared with a couple of different suppressors on it.
It is certainly nice to know that the option is there, though I don’t think it would be too hard for Sig to make a three or four-position to give a little more customization options.
The lightweight handguard of the MCX Spear is comfortable and easy to work on.
MLok slots all over give the user many options to customize the rifle and put accessories where they want them. And if you choose to swap the barrel out of your rifle, the handguard is easily removed to allow access to the barrel trunnion and its clamping screws.
The Flatblade match trigger in the Spear was outstanding. A much better trigger than I anticipated in an SBR, and it likely helped with accurate shooting.
This is the kind of trigger I would expect in a nice DMR-type rifle, and it was very welcome for me.
How We Tested
I shot the MCX Spear LT over a few range trips, using the aforementioned Hornady ammunition and some PMC Xtac 55-grain ammunition. For the majority of the shooting I used an EOTech holographic sight, which I might add is an excellent option to go with the Spear.
Shooting the rifle was mostly done at closer ranges, mainly because I think that’s where rifles of this configuration shine. Pulling the rifle out in a vehicle showed how handy the little SBR can be, and shooting it from the folded position also put its utility on display.
Reloading the rifle was smooth and seamless, mainly due to the ambi bolt-catch I already mentioned. The Pmags flowed in and out of the magwell through a great many reloads, and it felt like the kind of rifle you’d want in a gunfight, should such a thing happen.
Hornady Black ammunition was used for the majority of my testing. The 62-grain load worked great in the rifle. I also used several boxes of the PMC Xtac 55-grain ammo and some Frontier 55 grain HP loads.
All of them worked well, but the 62-grain load was for sure the best in this rifle.
Rifle ran flawlessly for the duration of my testing.
With the customization utility of the MLok handguard, I think you could set this rifle up to be perfect for you. Out of the box, it is not bad at all, either.
The buttstock options, while awesome, are also slightly limited. I’m still mad bout the Rokset muzzle brake.
Dead sexy. Nothing more to say.
The Spear LT is not inexpensive, with a street price of around $2500.00 it could be tough for many to justify. But if you were ever gonna splurge on an SBR, splurge here.
I’m a sucker for optical sights, the EOTech seen here was a perfect match. Check out our EOTech EXP3 review for more info on this optic.
But any good comparable sight would also work great. Something like the Aimpoint Comp M4.
A good single-point sling would serve you very well with this petite rifle.
Everybody has their preference, but something like the Brownells AR15 single-point sling would work.
The Sig SLX556-QD is probably the only one I could recommend since I can’t remove the muzzle brake.
The Mk18 would make a very comparable and good choice to the MCX Spear; though it doesn’t fold like the Spear, it still features many of the same good features and has a distinguished service record.
Another good choice with even further reduced size is the Maxim Defense MD15. The very short 5.5-inch barrel and collapsible stock make it even more compact in size than the Spear LT.
The Sig Sauer MCX Spear LT is an excellent choice for a defensive rifle, a sport rifle, or really for almost any other shooting activity suited for an SBR.
It brings Sig’s high quality and service standard to a very handsome and usable rifle without having the large footprint of a full-size rifle. If you are in the market for a good SBR that you’d want in a life-or-death situation, the MCX Spear LT would surely be at the top of my list.
Let us know what you like about the Spear and how you’d set it up if it was yours.