TFB Review: SIG Sauer MCX-SPEAR 7.62×51 SBR

There has been a lot of talk in recent years about the new SIG Spear or the XM7. Many discuss whether it’s a worthy replacement for the venerable M4 and the pros and cons of moving to a higher-power cartridge. Many discuss the theoretics of a near-peer threat with armor and extended engagement distance while others talk about a reduced combat load of ammunition and the inability of your standard grunt to take advantage of the extended range of the 277. I have always found myself drawn to platforms like the ACR and SCAR that touted themselves as M4 replacements, so I decided to get my hands on one and put as many rounds through it as I could to see if it’s something worth picking up as a civilian. 

First Impressions

When I first got my hands on the Spear, one of the first things I noticed was the heft, despite being an SBR with a 13-inch barrel, the Spear clocks in at a hefty 9.2 lbs bare with it fully kitted out with a scope, light, LAM and mag it was well over 13lbs. Despite the heft, the gun is fairly well balanced making it very shootable and easy to run and gun with. Over the course of the review, I have put over two thousand rounds of various 308 Win ammo through it. On my first range trip, one of the first things I noted was how smooth the recoil impulse was with the gun, while definitely a battle rifle it handles surprisingly well. One of the first things I did to the gun was put a 2-chamber brake on it and it remained in that configuration for pretty much the entire review. The stock flash hider seems to perform terribly with a much sharper recoil impulse while still remaining uncomfortably loud. With a brake, the best comparison I can make to it is a well-tuned AR10. Typically piston operated systems deliver more felt recoil than their direct impingement counterparts so this was surprising to me. 

Range Time

Over the better part of a year, I put over 2 thousand rounds through this gun from running and gunning to engaging targets off tank traps at 600 meters plus. It has not had a single issue with any of the ammunition I have put through it so far. I have used everything from match-grade ammo to bulk M80 and steel case. The Spear has managed to chew through everything I threw at it. With match-grade ammunition from Federal and Hornady the Spear is able to get just under 1 MOA 10-shot groups repeatedly with it sitting at about 1.7-2.1 MOA with ball ammunition. All groups were tested off bags with a mark 5 5-25 to ensure the best chance at accuracy. Early in the year we took the Spear out to Bend, Oregon, and shot it out in the badlands at the engagement distances it was theoretically designed for. On steel out to 700 yards despite the short barrel length the Spear performed admirably, easily making hits on smaller gongs at range. 

The Spear despite its weight is extremely well-balanced and lends itself well running and gunning. I was worried that the rifle would be clunky and cumbersome running drills but it handles like a much lighter gun when moving and shooting. The trigger the Spear comes with is crisp and fairly light which allows for some pretty fast splits. During a shoot, we ran an assortment of drills and we all agreed it performed better than both my buddies’ SCAR and the SFAR we had out. When compared to the SCAR, the Spear handles better and shoots flatter and settles faster under recoil. Friend of the show Fong, an M-class USPSA shooter, agrees with me that the Spear is one of the best 308 gas guns on the market. He runs his Spear like it’s an AR15, watching him tackle a stage; it’s almost like there’s no difference in caliber at all. Footage provided by Fong from a match hosted by SOLGW.

Ergonomics

The controls on the Spear are extremely well thought out, easy to use with gloves and incredibly intuitive. The ambidextrous lower is one of the best I have run and I compare it to others like the Radian ADAC in its ease of use. The ambidextrous bolt lock and drop is in the perfect spot and just the right size to balance ease of use while not being oversized enough to get caught on kit or get in the way. At first, I was skeptical of the dual charging system with both a traditional AR-style T handle and a folding side charging latch. After over a year of using it, I find it difficult to go back to a normal AR charging handle. In colder weather especially with gloves the side charging was by far the easier option and became my go-to throughout the review process.

The rest of the rifle is well thought out as well. The handguard, while thicker than a traditional AR, is still very comfortable and provides a solid lockup with no discernable wiggle. Without the Arisaka rail clamp it did show some zero shift with a LAM but I only put about 200 rounds through it at night so I was unable to fully test the extent of the shift but when properly torqued it was not enough to throw the aim off a target at 120 yards. 

The length of pull with the folder is a little long for my liking when fully collapsed however it’s still very usable. The folding stock makes packing the gun up for the range a breeze and it fits in even my smallest cases without an issue. I can even fit an 11.5″ AR15 and the Spear in the same case with relative ease. 

The Magpul SL-M stock the Spear ships with is a good fit for the rifle allowing it to remain slim when folded but also provides an adequate cheek weld for shooting. I noticed in the colder weather in the badlands the stock would tend to stick and not want to collapse unless given a good hit, however, this was fixed with some light grease.

Reliability

Over the course of the review, the Spear had maybe 2 malfunctions both of which were related to bad ammunition. Aside from keeping it oiled, the Spear was only cleaned once during the entire review at about 650 rounds. After which it was run intentionally dirty to see if I could get it to choke. The standard gas setting on the Spear is very generous and allows the gun to work through dirt and carbon with ease. At the tail end of the review, I put about 800 rounds through the gun as fast as I could load magazines much to Hop’s chagrin. By the end of the range day, we were all thoroughly concussed but the rifle had still not had a single malfunction. I think the combination of the rifle being slightly overgassed with the piston-operated system leads to a superbly reliable rifle. As a testament to this after shooting the last of my 308 Win ammo, I took the rifle apart and while dirty it was shockingly clean considering the amount of rounds shot through it since its last cleaning.

I was able to run the Spear suppressed briefly with a friend’s Huxwrx Ventum 7.62 and it was a match made in heaven. The added benefit of suppression with none of the downsides of the extra gas in the face or additional fouling. The gun handled about 400 rounds suppressed with no issues or notable increase in sluggishness. Additionally, the gun chewed through about 200 rounds of Tula 150gr steel-cased ammunition with no issues. Although we did have several dud rounds in that batch that refused to ignite no matter which gun we tried to fire them from, the gun never failed to cycle whatever we put through it.

Suppression

Given the Spear comes in a 13-inch SBR configuration it makes the rifle a prime candidate for suppression. In my time with it something I wish I would have done more is run it suppressed. Without a suppressor, the concussion of the rifle necessitates doubling up on hearing protection as it’s essentially a giant concussion grenade every time you pull the trigger. I found that the suppressor setting on the rifle’s gas block functioned as intended and did a good job of mitigating excess gas back to the shooter while ensuring reliable function. 

I personally think one of the best suppressors to pair with the Spear is the Huxwrx 7.62 Flow Ti. The flow-through technology not only allows you to mitigate toxic lead and carbon back into the system even more than changing to the suppressed gas setting would allow but it also greatly reduces recoil with excellent sound suppression. Additionally, the Flow 7.62 is fairly compact and lightweight coming in at 11.8 oz and only 6.7 inches long. The grade 5 titanium used in the 3d printed body is extremely durable and in my opinion, makes it a perfect fit for the Spear. 

When you start shooting as much as I do, you quickly come to appreciate the benefits of reduced back pressure suppressors. While they may not be as good as traditional suppressors in flash suppression or noise mitigation at the muzzle, they typically perform excellently at the shooter’s ear. Such suppressors also allow the gun to function with minimal increase in back pressure allowing the gun to cycle cleaner and longer before maintenance becomes necessary. Additionally, if you don’t want to tune your gun to a specific suppressor, low back pressure suppressors like the Flow 7.62 Ti are a phenomenal option. If you are interested in picking up a Flow 7.62 Ti they are available at Silencershop.com.

Overall, while I don’t think I understand all of the reasons why the army is moving to the Spear with the new XM7, I can agree that it’s an extremely well-built rifle. Over the course of the review, it proved to be rugged, reliable and an extremely fun gun to shoot. I had the opportunity to get time on a Spear chambered in 277 Fury and I think that the capabilities of the round are phenomenal despite the significant jump in recoil compared to 5.56. 

The Spear goes for $4100 from retailers which is a hefty price tag. However, compared to other options on the market like the SCAR 17 NRCH which comes in at a similarly hefty $3850, I personally think the Spear is worth the price tag if you want one of the best semi-automatic 308 rifles on the market and something different than an AR10. The Spear comes with a fully ambidextrous lower as well as a dual charging system and in my opinion handles and shoots better than the SCAR despite the significant difference in weight. If you are looking for one of the nicest battle rifles on the market and you have the scratch look no further than the SIG Spear.