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Airsoft, or pellet gun versions of real firearms that are licensed for manufacture by gun companies, are awesome for a lot of reasons. They’re a lot of fun to shoot. You can use them as training tools that offer better feedback than dry firing. What’s more, ammo is cheap, and you can get them shipped right to your door (in most states). The all-metal airsoft SIG Sauer Proforce MCX Virtus is an excellent example of one.

In this SIG Sauer MCX review, we’ll look at the airsoft version of the gun. Spring-powered guns can be low-powered. CO2 guns have a bit of punch, but you have to buy and change out those 12-gram canisters. Then there are electric guns like the MCX Virtus Airsoft AEG (Auto Electric Gun). That gun uses a battery-driven gearbox and spring to compress air and fire pellets. As long as you have charged batts and pellets, you can keep shooting. But you can use this airsoft gun for training even without them.

SIG Sauer Proforce MCX Virtus AEG Airsoft Specs

  • Type: Auto Electric, battery powered
  • Action: Selectable semi-auto and full-auto firing
  • Caliber: 6mm
  • Projectile type: 0.2 g airsoft pellets
  • Feet per second: 370-420
  • Sights: none, full-length top rail
  • Weight: 7 pounds
  • Required Accessories: 11.1V LIPO battery and charger (not included), ammunition
  • Price: $360

What Kind of Air Rifle is the SIG Sauer Proforce MCX Virtus AEG?

Close up of the SIG MCX Virtus airsoft
The SIG Sauer MCX Virtus airsoft rifle is an accurate replica of the real thing. David Maccar

This gun is ideal for fun plinking and for training using the centerfire version of the gun. It’s built around a VFC gearbox, spring, and hop-up, making it robust and reliable.

The SIG Sauer MCX Virtus airsoft rifle is pretty much identical to its real-gun counterpart. The only visible difference is the wires. You can see them through the handguard and the big, orange, three-prong flash-hider on the muzzle. The markings are even the same, serial number and all.

Everything is here and everything functions—and take a second to appreciate that. Not only did they have to design a gun that uses an electric gear box and piston to fire little plastic pellets, and do so accurately, but they had to fit it all into the form and function of a carbine designed to fire 5.56 and .300BLK.

The magazine holds the airsoft ammo, the ambi charging handle retracts the “bolt,” the bolt release releases it, and the ambidextrous mag release functions like the real thing. The forward assist is even there and is under spring tension, though I don’t think it actually does anything. The upper and lower receivers aren’t plastic, they’re aluminum. Honestly, you couldn’t confirm it’s an airsoft, even after picking it up; you’d have to pull the bolt back to be sure. The quality that is present in other SIG Sauer rifles is here.

The telescoping PDW buttstock is the same one you’d find on the real MCX Virtus, and it includes a QD sling attachment that matches with another set on the handguard. It’s also removable, so you can run it without a stock, or with the stock of your choosing.

There’s a full top Picatinny rail for any combination of real optics, red-dots, and magnifiers you want to train with, and plenty of genuine M-Lok slots in the aluminum handguard for accessories.

The handling and weight of the receivers is very comparable to the real MCX of this length, but the front end is a bit lighter than the genuine article just because it isn’t sporting an all-steel barrel.

How Does this SIG Sauer MCX Airsoft Gun Work?

Close up of the SIG MCX's battery
The batteries are concealed in the handguard. David Maccar

You’ll find the operation of the airsoft SIG Sauer MCX simple once you get the gun set up. First, you have to install a charged battery. The gun actually doesn’t come with one, which is kind of surprising. SIG recommends using an 11.1V LIPO rechargeable battery and appropriate charger.

These batteries are pretty common in the hobby world. They’re used to power RC vehicles and all kinds of things. You can get a two pack on Amazon for under $30. But, again, a charger is separate and can run you an additional $11 or more. I shot in semi and full-auto alternately for about two hours or so before a single battery went dead. Be warned, these batts take several hours to charge, so having a backup is a good idea.

Once you have your battery squared away, connect it to the wires and fuse near the barrel. Next, tuck the battery in above the barrel and replace the handguard. Then, load the magazine, which will hold 120 6mm airsoft pellets. The included speedloader makes this fairly easy. 

The mag doesn’t seat as positively as I’d like. You have to tug on it to make sure the catch is engaged.

After you insert the magazine, you’re good to go. Just flip the selector from “safe” to the semi-auto or full-auto notch and squeeze the trigger. Don’t fire off a full 120-pellet mag in full auto; it could cook the gear box. Stick to realistic bursts.

When you’re done shooting, eject the mag, fire a couple times at the target to make sure there are no pellets in the chamber, and return the selector to safe.

How We Tested the SIG Sauer MCX

Airsoft pellets feed this SIG Sauer MCX
Brightly-colored pellets help with clean up. David Maccar

The range testing for this guy took place in my garage and basement. I turned some shipping boxes on their side with the bottoms facing me and the opening facing a backstop (and old piece of fiberboard). Stickers from old targets served as bullseyes. The pellets went right through the cardboard and collected inside the box, for the most part.

Just know, once you shoot a number of airsoft pellets in any indoor environment, you will continue to find those pellets for literally years. Using bright green pellets does help with clean-up though, and biodegradable 6mm pellets are available for shooting outdoors.


Accuracy isn’t a huge concern when it comes to training with an airsoft gun, but it does have to hit it’s intended target at reasonable distances.

I didn’t adjust anything on the SIG Sauer MCX before letting off the first full-auto burst. I thought it wasn’t feeding right as there was just one ragged hole in the carboard, but no, there were 10 pellets rattling around in the box. 

A line of empty cans and semi-auto mode proved that this sucker is super accurate at in-the-room distances, and being an AEG, it will fire full power until that battery conks out. At 20-paces, it was just as accurate. With a set of folding iron sights mounted on top, I don’t think I missed a single shot.

Since the upper and lower receivers, as well as the handguard, are all aluminum and the pistol grip and PDW stock are identical to the real thing, this airsoft version of the MCX feels and handles a lot like the real deal. It’s a bit lighter in the front end, since there’s no all-steel barrel to heft around, but it by no means feels like a toy.

While the charging handle and bolt release don’t actually do anything other than open the dust cover and expose the hop-up adjustment screw, they still function and can be used for drills. Even the forward assist has a spring in it and “functions.”

The ambidextrous mag release and selector switch work like the real thing too. If you manually lock back the “bolt,” you can perform reload drills with additional magazines, but the gun only comes with one and the plastic mags are super lightweight. And no, you can’t use real empty 5.56 mags, I tried. The mag catch on the gun is positioned too high for the notch on real magazines.

Hits and Misses

SIG’s apparent goal with this rifle was to create an airsoft version of the MCX Virtus that’s as close to the real thing as possible, and they succeeded. The fit, feel, and finish of this gun are excellent and it works perfectly with QD slings, M-LOK components, and Pic rail optics for all sorts of training options. The controls are spot on, and so are the ergonomics. Airsoft enthusiasts might complain that the selector switch is a little mushy and that the magazine isn’t the best, but for training purposes, they both work just fine.

As a trainer and fun plinker, the Proforce SIG Sauer MCX Virtus is outstanding—you can’t count this one amongst the ranks of cheap bb guns. But remember that this is an airsoft model, so pick up a pellet gun instead whenever you grab your hunting gear.

I wish the gun came ready to run out of the box. Also disappointing is the singular included magazine and lack of even simple iron sights. With a price tag of $360, an owner who realizes they now have to drop another $40 minimum on batteries and a charger and attach some kind of sighting mechanism has the right to be a little pissed off and inclined to return the gun.

The BB Option

SIG Sauer MCX Scope Combo

The SIG Sauer MCX Scope Combo offers CO2-powered BB fun.

If $360 seems steep to you, you can get your hands on a CO2-powered version of the SIG Sauer MCX instead. Switching from battery power to pneumatic means you lose the full-auto capabilities, but you save a bunch of coin on the purchase. The SIG Sauer MCX Scope Combo sells for about $230, so you’ll have plenty of cash left over for CO2 cartridges. And the gas-fueled SIG Sauer air rifle comes with an optic, so you won’t have to get your own.

Does the SIG Sauer Proforce MCX Virtus AEG Deliver on its Mission?

This gun is outstanding in feel and function. With the airsoft version of the awesome MCX Virtus, SIG has delivered a fun way to practice and train practically anywhere with something close to the real thing.

You can use it to blast cardboard and cans in the backyard all day, safely, and you can conduct any kind of dry-fire or non-firing drills (like room clearing) with a much higher degree of safety and without worrying about live ammunition being around, while also using all your real-gun accessories. Plus, you can get 10,000 6mm pellets for less than $30. That’s a lot cheaper than .22LR, and last I checked, they don’t make an MCX is .22LR.

As far as shape and size, it’s identical to the centerfire version, and the weight is darn close too. The controls are identical, it’s accurate as hell, and the battery pack fits in what would otherwise be empty space under the handguard.

All-in-all, this is a great training airsoft that will allow you to run drills for the real SIG Sauer MCX, or any short-barreled AR platform firearm, that are a level above dry-fire without burning precious and expensive ammo. You can also use the gun for force-on-force training (with proper supervision and safety equipment) and even airsoft competition.