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At a recent media event held at HighSpeed Gear’s headquarters in North Carolina I had the chance to spend some quality time with the new Sig MCX VIRTUS. Aside from now being available in ultra operational grey as well as tactical peanut butter the MCX VIRTUS has a few practical upgrades over the standard MCX.

SIG wisely dropped the keymod handguard and has joined the M-LOK club. The new handguard also features holes that allows the end user to adjust the two-position gas block one for either suppressed or unsupressed fire. While those holes are useful for adjusting the gas block they also present an opportunity for burning your fingers when the barrel is hot, if you’re not careful. This feature I can confirm.

With a little training or more intelligence than I have this is easily avoided. The handguard has two areas to access the gas block because the gas block location changes with barrel length.

Like the previous MCX, the handguard is easily removed by pushing the forward takedown pin and sliding the handguard off. The SIG rep said zero retention is pretty reliable, though he recommended mounting the backup iron sights on the bit of rail that’s attached to the upper receiver, though doing that reduces your sight radius dramatically.

Like the MCX the barrel can be changed by removing two screws. I like the easily removable hand guard. It’s comfortable and sturdy. With the VIRTUS, SIG also released eight new handguards of varying lengths and internal widths to accommodate suppressors.

The new stock is still a side-folder but the butt stock has five length of pull positions. It’s sturdier than it looks and rattled much less than a lot of M4 style stocks I’ve tried. The adjustment button is solid and the lock-up is tight. Folding the stock takes a fair amount of pressure, however. When extended, it’s as tight as any non-folding stock.

The VIRTUS has a polymer insert in the lower receiver to ensure a tight fit with the upper receiver the original MCX made do with a screw.

As you probably can’t tell from the picture above, the VIRTUS features a spring loaded firing pin.

You get your choice of a 9″, 11.5″ or 16″ cold hammer-forged barrel chambered in either 300Blk or 5.56. The Virtus barrel has a heavier profile than the standard MCX.

The new SIG Matchlite Duo trigger is a satisfying two-stage trigger. It’s smooth, though the pull is a bit long as is re-set. Still, much better than your garden variety mil-spec trigger.

Shooting the SIG Virtus was a pleasure. The recoil impulse was smooth, muzzle rise was minimal and it proved completely reliable for the 200 or so rounds I put through it. I have two minor complaints, and I am really nit picking here. Inserting a full magazine is a challenge when the bolt is forward. Also, there’s that gas adjustment slot in the hand guard which can scald your digits. Still, After shooting the VIRTUS for a day I walked away wanting a lot more time with one.

Our man Leghorn gave the original MCX a four star overall rating and described it as “trigger-denied perfection”. With the addition of the Matchlite Duo trigger, the VIRTUS might have inched even closer to perfection. That near-perfection comes at a cost, namely $2,233.

Further testing and a full review is forthcoming. Who knows, we might even let Leghorn out of his cage to give the VIRTUS a go.


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    • This is not a full review. This is just a short range trip writeup. Full review will happen eventually, probably.

      • I TOTALLY agree! Sig is not an engineering company like they used to be and still claim to be! They are a marketing company and release products due to SHOT show timing and other key dates – not when the product is actually ready to be released. Want some examples??
        How about the original MCX (a complete, total disaster). How about the the “Drop and Shoot” P320, that they vehemently denied had an issue till proven wrong by simple 8th grade science project replications on YouTube ! And finally the highly vaunted, rushed to SHOT Show, “FTF” P365! All are perfect examples. But opps! ONLY the last three major product releases they had!!!!

        Until SIG stops being the arrogant, turd pies trying to blow pure marketing smoke up my butt and starts FULL TESTING of new firearm designs like an engineering driven product line should be – I won’t buy a thing anymore from them.

  1. Since the original MCX bolt is being exchanged by Sig at not cost, the only major changes are the trigger and the rail it seems. I rubber/plastic/polymer insert is a 5 dollar accuwedge so I don’t see that as major.
    At 2200 bucks, I’d find the original MCX and make the changes myself and put 300-500 dollars in the bank.

    • It sounds like it has a slightly different handguard as well as a heavier barrel profile.

      • The barrel must be heavier as the spec or the gun is quite a bit heavier than the original. I like pencil profile barrels so I think I’d still opt for the older version to save $$$.

  2. Am I missin somethin or is this similar to a cross between an AR15 and an AR180? Looks like a fun baby regardless.

    • Or a POF 415? $2000, similar operating system. Spend the $200 saved on a nice red-dot or a brick of ammo.

      • Never had any trouble with my keymod rails or accessories…then again…I’m not operating operationally or throwing my rifle off the side of a mountain.

        • I find that the sharp corners on the Keymod slots tend to be a bit snagy. It’s a minor thing, but the first time one of them catches the edge of your sling and jacks up your shoulder transitions will make you want to throw the hand guard across the range. I own exactly one Keymod rifle and it is only acceptable because it’s a 14lb heavy barrel .308 bench gun that I won’t be taking to any dynamic competitions in the foreseeable future. MLok is a clearly superior standard with better rigidity, mounting options, and overall feel. Keymod is better than a picatiny cheese grater, but it’s a distant second to MLok.

        • The SOCOM KeyMod vs. M-LOK test results can be found online, and they’re quite significant. Removing and replacing accessories maintains zero significantly better with M-LOK, and the drop testing was 100% success rate with M-LOK vs 33% for KeyMod. The KeyMod rails were prone to failing by the hand guard splitting/fracturing between slots, whereas the M-LOK accessories/rails would just slide back a bit in the slot with no permanent damage to hand guard.

          It was rather conclusive, and when hand guards of each type cost the same amount, and accessories are more widely supported for M-LOK, it only makes sense to use it in most/all applications.

  3. Here is fair warning to anyone looking to purchase one of these. Since the release of the Sig-556 around 2007, Sig has ricocheted from one proprietary design to the next, rarely sticking with one design for more than a year or two while allowing end users to be the Beta testers on products that weren’t quite ready for prime time. Within about three years of purchasing two Sig rifles, I was unable to get proprietary replacement parts, even minor items like springs and pins, and they never were available again. So these were essentially $3K worth of disposable rifles.

    Really look at the crazy release schedule of them changing rifle designs again and again and again and not having replacement parts available for them ever really being available. They might have a few limited parts for one year, after the rifles have been out for a year, and then never again.

    Seriously, I was a hardcore Sig fan. I own the aforementioned two rifles and seven Sig handguns, but their quality control and Beta testing has gone the way of the Dodo. Not hating on the company, but quite frankly, they truly aren’t what they once were. Just do some research into what I am saying. Buggy products, no replacement parts. Don’t say I didn’t tell you so.

    • I agree. I have a problem with Sig in that they make way too many products and their turnover is horrendous. They are overly diverse and I don’t see how quality can be maintained with so many products. When shopping for a rifle it is better to focus on a company that specializes in them. For a piston AR, I’d go with LWRC. I do own an original MCX but will probably never buy another Sig rifle again, because other companies (LWRC, BCM, KAC) just do it better. Hell, even the P365 pistol has had issues.

  4. That may be true, but Sig has the modularity the LWRC , POF, and KAC are lacking for a Mission configurable platform. This is why it has been chosen by some of the elite forces.

    • Right, but the issue being mentioned is that replacement parts are proprietary and Sig has a bad habit of putting out a new rifle line every year or two, and then discontinuing the older models. In 2-3 years Sig may no longer carry or make replacement parts or barrels/handguards, meaning your $2000 rifle can’t be properly maintained. A lifetime warantee doesn’t mean much if the company no longer has the parts to fix the firearm.

      This has happened with several of Sig’s recent rifles, so it’s a reasonable concern to worry about longevity of support for the platform.

  5. I have the Sig earlier version and it came with two barrels 556/300 BO I would like to SBR it and get the Shorter barrels but they don’t seem to be available….anywhere…..while it is a modular platform, whats the point when you can’t get the other parts to go on it and change it up. I agree that Sig does not support their firearms with parts. same goes for Proprietary mags….Sig discontinued the p239… I have one can’t find mags. I do not plan to purchase any more Sigs. I love my MCX but If I can’t get a shorter Barrel to SBR it, I’m going to sell and go with just build what I want.

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