Review: SIG Sauer's MXC Air Rifle

posted on August 29, 2018

No beer can is safe around my place. That’s not entirely due to my Wade Boggs-like taste for suds, but more so that I bought myself a SIG SAUER air gun and now I toss cans into my back yard and riddle them full of holes before I recycle them. Beer cans, soda cans, green bean cans (if I ever ate any vegetables), cardboard boxes, small rodents, whatever; they’re all fun to zap with pellets, especially when I don’t have to pause to reload.

That’s because SIG's new MCX air gun is modeled after its MXC line of sub-gun rifles. It’s a semi-automatic .177- or .22-caliber pellet rifle that holds 30 rounds in its innovative detachable magazine; it looks and feels surprisingly close to the real thing. Inasmuch, I enjoy useful carbine practice at a fraction of the price. The controls, the weight, the sight picture—it’s all there—but without the neighbor-alarming blast of a centerfire.

To be clear, this air gun is not exactly kids' stuff. It’s an adult-intended air gun that uses bottled CO2 to drive pellets to an advertised 750 feet per second (fps) as fast as you can pull the trigger. At 5 yards, it’s easy to mistake it from the real McCoy, complete with its faux forward-assist button and bolt release on its aluminum die-cast receiver, which is painted either black or earth-tone tan. You won’t find any toy-like orange on this baby, because it's not a toy. Its working controls include an ambidextrous AR-15-style safety, magazine release button and charging handle. Atop the receiver is an integral metal Picatinny rail that transitions perfectly to the rail of the polymer handguard, allowing shooters a full-length rail to mount lights and optics just like their real rig. It comes with detachable flip-up sights. KeyMod-style holes on the handguard allow for attaching other accoutrements, such as the included plastic vertical foregrip. Ahead of the handguard protrudes the MXC’s 18-inch barrel, which mimics the appearance of a silencer...because what sub-gun doesn’t look better with a silencer? Of course, this air rifle doesn't actually have one because it doesn't need one, producing minimal noise.

The two most notable features that required a good deal of engineering and that actually affect the air rifle’s performance are its 30-round detachable magazine and the buttstock/CO2 reservoir system.

To load the rifle, remove the magazine, flip open its small, hinged window and remove the pellet belt. Manually load up to 30 pellets into the belt by pressing each one into a sleeve. Then reinstall the belt into the magazine. Considering the difficulty of automatically chambering small, soft lead-skirted pellets, Sig’s belt-fed solution is a sound one.( More on loading and shooting later.)

The pellets are powered by a 90-gram, non-refillable cylinder/bottle of CO2 that’s hidden by the tank shroud/buttstock. To load a fresh cylinder, press the buttstock release button, remove it, then screw a cylinder tightly into the threads as quickly as possible. Replace the buttstock, then pull the charging handle back just as you would an AR-15. You’re ready to shoot. And now with the technical details out of the way, here’s what I learned after shooting the MCX.

Training factor aside, the MCX is tons of fun for the whole family. It makes hardly any sound, it’s recoil-less, yet it fires faster than Bruce Willis in Die Hard. I averaged 1.55-inch groups at 15 yards. It measured 110 on my sound meter. To put that in perspective, it’s about like an small audience of mice clapping loudly.

I mounted a red-dot optic and practiced tactical maneuvers such as pie-ing corners and quick target acquisition from a low ready position. But that only lasted a few minutes until I was overwhelmed with a desire to plug beer cans while sitting on my porch. Soon enough, my nephew and I engaged in some trick shot wagering with the MCX, all under the nearest neighbor’s nose. Despite its 30-round magazine, the rifle seems perpetually empty!

I learned the hard way that once a fresh air tank is screwed in, it can’t be removed without wasting the remaining C02. Bottles cost around $9 from online sources, and each one lasts approximately 400 shots. It should be noted, however, that the gun's velocity drops as the tank’s pressure lowers. To that end, the MXC wasn’t close to SIG's 750 fps claim. According to my chrono, 350-500 fps was more realistic.

Loading the belt-style magazine is very tough on the fingers. After loading a half-dozen belts even Eddie Van Halen’s fingers would need a rest. I recommend using a thimble to start each pellet. Then after all 30 are started, turn the belt upside down on a flat surface and press down hard to fully seat them.

One more concern was my test unit’s trigger. Now, I’m not expecting perfection in a $200 air rifle’s trigger, but several times the pseudo-double action trigger mechanism jammed midway through a magazine. I soon found that this was caused by failing to fully seat each pellets, which can jam the belt and therefore the trigger. From then forward I made sure the pellets were seated flush. Then I fired away, wasting beer cans like Sylvester Stallone does bad guys.

All in all, the MCX is a super-fun adult air rifle that has a purpose. Even so, it’d make a great gift for any gun guy or girl, regardless of age or experience. 


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