I had recently had the privilege to write about SIG Sauer’s Ammunition Factory for the March-April 2018 issue of World of Firepower. I discussed SIG’s new factory in Jacksonville, Arkansas, the company’s dedication and commitment to quality, and its goal to truly become a “complete systems provider” branching into virtually all realms of industry production—firearms, suppressors, optics, ammunition and even training.

I came away impressed by the production capabilities of the ammunition facility. Unknown at the time , a few weeks later I’d have the opportunity to see how well the SIG ammo actually performed in a recently released and updated version of the SIG Sauer MCX platform called the Virtus. In August 2017 I was invited to attend a two-day writer’s event at the esteemed SIG Sauer Academy in Epping, NH. Along with several other industry writers, we spent two range days with SIG staff, ran through several different configurations of the MCX Virtus rifle and learned to appreciate the different iterations of the weapon platform. After introductions, safety briefings and SIG program discussions, we got into the meat and potatoes of what the MCX Virtus platform was all about, and got a chance to take our assigned rifles into the armorer’s room for a mechanical runaround.


The MCX Virtus, as we quickly learned, is a highly adaptable, highly configurable platform. Built off a smart short-stroke piston design, the MCX is offered in different barrel configurations and calibers, ranging from a standard 16-inch 5.56, to an 11.5-inch in both 5.56 and 300BLK, to 9-inch barrels in 300BLK. To increase performance and adaptability even further, each barrel configuration also boasts a suppressed/unsuppressed switch at the gas key to properly regulate gas flow so the end user can go quiet(er) in any configuration as mission parameters dictate.

Barrel interchangeability means that the Virtus’s rail systems must also be flexible and adaptable. The MLOK handguard is unique in shape; it is more oval than rounded, with traditional Picatinny rail at the 12 o’clock position, and M-LOK slots at the 3 , 6 and 9 o ’clock positions for all of your accessory needs. What I really appreciate about the rail is that it flows seamlessly into the upper of the Virtus and lends itself to an uninterrupted monolithic look. SIG offers MCX handguards for each barrel designation, as well as properly lengthed handguards for running a build with or without a suppressor.

The MCX is offered in different barrel configurations and calibers, ranging from a standard 16-inch 5.56, to an 11.5-inch in both 5.56 and 300BLK, to 9-inch in 300BLK.

Removing the handguard requires no tools, as it is secured to the upper receiver with tension and locked into place by the front takedown pin. All the end user has to do to remove the handguard is to pop open the front takedown pin, apply a hearty squeeze and elbow grease to the handguard, and it’ll pop off the upper receiver.

Swapping the barrels is almost just as easy. The barrel is inserted into the upper receiver and clamped into place using two captured Torx T27 screws. Simply unscrew the Torx screws, firmly grasp the barrel, and pull it out to swap to a different barrel length or caliber. Once the barrel is seated, simply re-torque the captured screws to their prescribed tightness and re-install the proper-length handguard. That’s it.

Due to the design of the short-piston system, a traditional AR-15 style bolt carrier group and buffer tube assembly is not needed. In its place at the rear of the receivers is an integrated section of 1913 rail to which different folding stock options can be attached. This inherent design advantage allows for folded-stock operation, as well as fixed stocks, pistol braces and even PDW-type stocks offered by SIG. The company currently offers several stock options to be custom-tailored to the end user ’s preferences. In a nutshel l, the user can reconfigure barrel lengths, calibers, handguard options, stock options, and run the build suppressed or unsuppressed all from one weapon platform, and all changes can be made with a single Torx T27 driver. Aside from the modularity of the system itself, the Virtus comes with a few standard options that I found very appealing as a lefty shooter. The integral ambidextrous mag release and safety selectors are a win for user-adaptability and a reduction in aftermarket accessory costs.


The end user can reconfigure barrel lengths, calibers, handguard options, stock options, and run the build suppressed or unsuppressed all from one weapon platform.

Also new to the SIG MCX Virtus is a Two-Stage Match Duo trigger system. The Match Duo is pretty darn smooth right out of the box, and while it won’t win any awards, it is definitely a step up and in the right direction. Are there better two-stages out there? Yes, there are, but for an already solidly-priced piston rifle, it’s nice to not have to immediately think about swapping in aftermarket parts to replace minimally acceptable components that many companies will just throw in to save a couple production dollars.

Now that we were familiar with the multitude of end-user configuration options, how did the Virtus shoot?

Day 1

We started our courses of fire with a 16 -inch barrel configuration using SIG’s SRD556 QD suppressors. The suppressors were amazing, but that’s for another article. With the 16-inch barrel configuration we started off with a basic 50-yard zero and spent the rest of the morning stretching out using SIG’s Tango6 1-6×24 riflescopes. From our 50-yard zeroes, we finished the morning ringing steel out to 700 yards. The writers in attendance were long-time industry writers with backgrounds in law enforcement, international armed forces and one former Group guy. All of us were having an easy day with the 16-inch rifles, especially with the SIG 77-grain match ammo. We wrapped up the morning session, had a lunch break, and then went to the armorer’s area to swap to a 11.5-inch 5.56 barrel. We replaced the Tango6s with Romeo4T red dots and headed back out to the short range for some close-quarter work for the rest of the day.

SIG Sauer provided verious courses of fire to illuminate the Virtus’s capabilities in a variety of real-world situations.

Once there, the staff ran us through a series of exercises and drills to get us used to more up-tempo weapon manipulations. The Virtus, despite the forward-biased weight of the piston system and suppressor, was very nimble. On the faster courses of fire, I quickly noted how much the Virtus shot like a standard DI gun; recoil was just as minimal, follow-up shots were easy, the rifle shot exceedingly flat, and the integral ambidextrous mag release button worked smoothly, with great ergonomics for my medium-sized hands. I also learned very quickly that I had been neglecting my long gun skills. The Virtus definitely shot better than I did that day.

Day 2

The morning of Day 2 was all about 300BLK. I am a big fan of the 300BLK cartridge and have built a few AR pistols in that chambering on my own. Despite the larger round, the Virtus ate everything we threw at it. I experienced a few hiccups, but that was only because I forgot to throw the gas key to the “suppressed” setting. A few friendly dueling tree competition rounds later and we gave the Virtus a break to spend the rest of the morning on the then-secret SIG MCX Rattler.

After lunch we had a chance to run the 9-inch shortie versions through an engaging Hogan’s Alley with courses of fire behind and through vehicles on steel targets from varying ranges, positions and left- and right-handed shooting stages. Competition heated up as we raced the clock and each other. We were hot, sweaty and in some cases a little humbled, but we all had smiles on our faces by the end of the course. I for one definitely need to get back to SIG Academy to give it another go!


We ended the day with the “Jungle Run.” We ran the scaled-down course, which was a good thing because I hadn’t been working on my cardio in a minute and was definitely feeling not so fleet of foot in my worn-out sneakers. Poor footwear choice on my part. The course started at about 300 yards with required hits on steel using the Virtus in the 16-inch barrel, 5.56 version. We would complete our hits at 300, run a wooded trail, take more shots from different positions and then swap to a shorter 300BLK configuration for 200 yards and closer. From there it was another short trail run back to Hogan’s Alley, where we engaged multiple targets at 50 yards using the MCX Rattler.

We wrapped the day up with many handshakes, business card exchanges, fond memories—and for me, a realization that I needed to do some serious work on my long gun skills.

Continued VIRTUS Follow Up Into 2018

A few weeks after I returned to the Pacific Northwest, SIG sent me its Patrol version of the Virtus—the standard 16-inch barrel model with muzzle brake, telescoping stock, iron sights and rail accessories. As the weeks went by, the company continued to send out accessories; a Romeo4T/Juliet magnifier combo, and a Tango6.

I started out my continued evaluation at my department’s range using the Romeo4T/Juliet combo. The familiar feeling of contentment from the low-impulse Virtus rushed back, and I spent a few quality range sessions shooting and moving between different positions on targets of varying sizes. I already knew from my time at SIG Academy that the Virtus was a shooter in various configurations, so my time at home with the rifle was more enjoyable than anything else.

Flash forward a few weeks, and the Tango6 arrived. This couldn’t have happened at a better time, as work and some local greasy politics had me stressed out and not loving life. Some range therapy was definitely needed. I mounted the Tango6 with some high rings, levelled everything and finally got some much-needed range time (and some sunny weather for a change).

Again, as recalled from my time in New Hampshire, the Tango6 is a money scope to be sure. Its glass is super-clear edge to edge, and the horse shoe reticle, although not my favorite design (this is just one of several reticle options SIG offers with its Tango6 line), made for very easy target acquisition up close or at distance. I’ll definitely get into this scope a bit more in the future.


Zeroing at 50 took about 7 rounds to get exactly where I wanted, and again, the SIG Sauer 77-grain Performance Ammunition made for an effortless 0.5-inch group at 50 yards. I ended m y extraordinarily satisfying range trip by shooting out six 1-inch circles at 100 yards as quickly as my sights could settle, and I was on them for all six. Not wanting to jinx anything, I packed up and called it a day.


The SIG Sauer MCX Virtus should be a crowd pleaser right out of the box. Ergonomically, it feels great for my small frame, and even as a piston rifle, with the weight inherently biased slightly to the front, the advertised 7.9-pound initial weight is easily managed. The weight-forward feel may also be slightly enhanced by the lack of weight in the stock assembly as there is no buffer tube/ buffer/buffer spring to counterbalance the piston system.

Out of the box, the SIG backup iron sights are hefty, durable, and I love how the front post requires no tool to adjust for elevation. Much like the Magpul PRO sight series, the front sight post has an integral dial system for quick adjustments in the field.

The SIG backup iron sights are hefty, durable and require no tool to adjust for elevation.

As mentioned, the Two Stage Match Duo trigger is a quality two-stage trigger— some users may not even switch it out for a different aftermarket trigger package. It definitely gets the job done with minimal grittiness, and its advertised 4.5-5 pound pull feels more like 4 pounds to my trigger finger.

The integral ambidextrous mag release is a great touch, and frankly, I don’t see why more manufacturers haven’t moved in this direction as well. Although the left-handed shooter market is one-tenth that of the rest of the shooting population, shooters overall are becoming more savvy. We realize that operating a rifle left-handed either out of positional necessity or in an injured shooter situation demands an equally flexible weapon platform, especially for LE and tactical applications.

We had a chance to run through numerous courses of fire, including through vehicles on steel targets from varying ranges, positions and left- and right-handed shooting stages.

The M-LOK accessories such as QD sling plates, both inline and offset, are an excellent touch. While I opted to use a Blue Force Gear U-loop for my sling setup (more for additional exposure and trigger time using it), the fact that SIG also offers those accessories for the discriminating buyer just further demonstrates the company’s thinking for the end user.


The only downside of the system is the included stock system. SIG offers multiple stock configurations and that’s a good thing, as I disliked the included stock. I found the adjustment lever to not be intuitive, and due to its rectangular shape, quickly adjusting it on the fly was difficult as it tended to bind which pulling it to lengthen the pull. I also found that while prone, even for someone as short as I am (5’3”), I wanted at least another inch to 1.5 inches of pull to really settle into a solid shooting platform.

While at SIG Academy, I was able to swap different stock models around, and I much preferred the more traditional M4-style stock option. It just worked better in multiple shooting positions. I would like to see SIG allow for the prospective buyer to have the option to choose their initial stock configuration prior to purchase.

All in all, the Virtus is a solid platform. Keep in mind that this is an initial review and I only have in total about 1,500-2,000 rounds down on this system. SIG Sauer claims that the Virtus’s internal parts will not need servicing or replacement until 20,000 rounds, which I didn’t come close to, but the longer the Virtus is in consumer hands out in the wild, we’ll see how it lives up to the claims of service longevity.

For now, I am having a very hard time boxing the Virtus up and sending it back.



MSRP: $2,233

Editor’s Note: A version of this article first appeared in the July-August print issue of World of Firepower Magazine.