New SIG MCX In 300 Blackout

One of the more appealing guns at the SIG event is the new SIG MCX. The MCX comes in several variants including an SBR,Carbine and pistol. The carbine and SBR have the new skeletonized stock with buffer pad. The pistol uses the next generation pistol stock which folds to the left as does the skeleton stock.

I was able to shoot the SBR version which in this case was select fire. The recoil was light and typical of an AR type rifle. The controls are all fully ambidextrous. The upper is a the monolithic type with a full length rail with no interruption. The forend rail system is a lightweight keymod with plenty of room for extras. All three versions come with a three prong flash suppressor.

MCX_9in_SBX_21985-F copy

All of my shooting was from the 50 yard line and 100 yard line. Firing in semi-auto I was able to hit the 1/4 size steel silhouette ten out of ten times. On full auto firing at the fifty yard target I was able to hit the target seven out of ten times. I’d say that’s pretty controllable. There is some muzzle climb but it’s strictly vertical with no rise to the right as many tend to do on full auto.



The optic used is from the new line of SIG optics they have named “Electro-Optics”. This model is a 1×6 power. The reticle on this particular scope had a vertical line with a red horseshoe center. The reticle was very easy to see. In fact this scope surprised me when I learned the tentative MSRP. I was expecting the cost to be at least $1200 or so just from the clarity of the glass and the general build. As it turns out the price will be right at $300. I can promise you at that price and the quality I’m getting one! This new optic line should become available in April. To answer the question that many have asked no this line of optics is nothing like the old SIG Tac scopes. These are quality and will start at $300 to the highest end scope at $1500.

Carbine with 16 inch barrel

Carbine with 16 inch barrel

SIG SAUER® Unveils the Next Evolution in Rifle Technology: The SIG MCXTM
NEWINGTON, N.H. (January 12, 2015) — SIG SAUER, Inc., continues to set new standards in firearm design, innovation, and performance with the introduction of the SIG MCXTM. Designed from the ground up as a short-barreled, silenced, lightweight rifle-caliber system, the SIG MCX has reset the standard for modularity, sound suppression, and mission capability.
With the introduction of the SIG MPXTM submachine gun, SIG SAUER raised the bar for performance and modularity in a pistol-caliber platform. The SIG MCX combines that modularity with rifle-caliber power in a compact package, designed for optimum performance with a silencer.
“We’ve built a team of the best minds in the industry, when it comes to silencer technology, rifle engineering and the .300 Blackout cartridge,” said Jeff Creamer, Executive Director and General Merchandise Manager for SIG SAUER, Inc. “The end result is a technological leap forward in ergonomics, modularity, cartridge performance, and sound reduction.”
Unlike every other firearm on the market, the SIG MCX was designed from the start for optimum performance with the .300 Blackout cartridge and a silencer. When paired with a SIG SAUER silencer, the outcome is a firearm with superior suppression capability and enhanced reliability with both supersonic and subsonic loads.
An auto-regulating gas system makes the transition from subsonic to supersonic seamless. In combat situations, the SIG MCX can run supersonic on the silenced setting without damaging the firearm or negatively impacting reliability.
Sharing a modular design with the SIG MPX, the SIG MCX is a mission-adaptable marvel. Changing between .300 Blackout and 5.56 NATO is as simple as swapping barrels and op rods. Converting to 7.62x39mm simply requires an additional bolt face change. All of this can be performed by the user in the field. Barrel lengths can also be changed, with 16″ and 9″ versions initially available.
“The SIG MCX can be set up as a silenced personal defense weapon or a primary rifle in almost no time at all,” Creamer said. “The one constant is SIG SAUER reliability and durability.”
PR Contact:
Allen Forkner Swanson Russell 402.437.6428
SIG SAUER® Unveils the Next Evolution in Rifle Technology: The SIG MCXTM Page 2
The SIG MCX features a revolutionary recoil assembly that does not require a buffer tube, allowing for side- folding stocks. A full-length picatinny top rail allows for the mounting of lights or optics. Removable SIG SAUER iron sights come standard.
The lower receiver offers familiar AR-style controls, with ambidextrous selector and mag release as standard. The SIG MCX upper is compatible with mil-spec AR-15 lowers and, with the use of a SIG MCX Stock Kit, allows consumers to fully upgrade their legacy system.
Three variants of the SIG MCX will be available to the commercial market; semi-automatic rifle, short-barrel rifle (SBR) and pistol configurations. All will be available in .300 Blackout, 5.56 NATO or 7.62x39mm, with caliber conversions available immediately.
All SIG MCX models will feature aluminum KeyMod handguards, ambi AR-style controls, an ambi charging handle, and will utilize standard STANAG magazines. Also unique to the SIG MCX is an upper receiver with hardened replaceable wear points, including a cam path wear insert, a feed ramp insert, a removable / replaceable deflector, and charging handle latch point inserts.
The rifle variant will feature a 16″ cold hammer-forged barrel, while the SBR will come with a 9″ barrel. Both will offer a choice of four stocks: a low profile, side-folding skeletonized stock, a telescoping stock, a tubular side folding stock, or a folding telescopic stock. The pistol variant will feature a 9″ barrel and a side-folding SBX Pistol Stabilizing Brace.
The SIG MCX rifle carries an MSRP of $1,866, while the SBR variant has an MSRP of $2,058. The pistol with side-folding SBX has an MSRP of $2,132.

Phil White

Retired police officer with 30 years of service. Firearms instructor and SRU team member. I still instruct with local agencies. My daily carry pistol is the tried and true 1911. I’m the Associate Editor and moderator at TFB. I really enjoy answering readers questions and comments. We can all learn from each other about our favorite hobby!


  • Patrick Karmel Shamsuddoha

    too expensive perhaps $2132 for a pistol, the rifle starts at $1866

    • Everything should be free!

      • Patrick Karmel Shamsuddoha

        No, Alex, that’s not my point, I feel like a more competitive price point could be found for these items. One that would add to the venerable amount of hype that has been attached to this project. It seems a vast majority of people have been intrigued by the CZ scorpion due to it’s price in comparison to the new Sig MPX and it may happen again with the MCX pricing structure. Now I do understand this new MCX is to be the Sig brands halo rifle so if that requires it to be at the top of the price marquis I understand that point.

      • Ebby123

        The thing is this Alex – People are willing to take a little risk on guns in the $400-$1000 range, but above that you’re in most people’s Holy-Grail, Once-In-A-Lifetime-Purchase range.

        Once you get that high people’s expectations get pretty unrealistic, and the reality is much less likely to live up to those expectations. (IE: “For $2000 that thing better aim itself, never wear out, make sandwiches and give BJs”).

        While I will build a gun that costs over $1,200, I will likely never buy one off the shelf unless it is literally the last rifle I ever need to buy.

        nawudameen? 😉

        • Not really, they have sold a lot of scars for $2300

          • Guest

            $2300 is about dealer cost on a SCAR 16S, FYI.

        • superflex

          I’ve never spent less that $1,000 on a gun.
          nawudameen cheepskate?

          • Mack

            Over compensating for something?

  • Dracon1201

    Unlike most modern combat rifles, I am actually interested in this. Hopefully Sig straightened up and improved their QC on their rifles. If that’s good and the accuracy reports are favorable, this may be a good pickup.

  • Knute Alred

    Why did I have to read to the press release before I found a comma?

    • Giolli Joker

      There’s one in the second sentence.
      There’s plenty of punctuation, separate sentences, no issues in reading.

    • Look harder:-)

  • LCON

    did Sig not also have a MCX CSASS on display there?

  • JQP

    I will be following the MCX (in 300 BLK/SBR) very closely in 2015. Very interested to see how it does in terms of Reliability, QC, and Accuracy. Being a piston, I don’t expect it to match a DI, but very curious what the difference will be. Know there have been some QC issues in the past, so hopefully that won’t occur with MCX. And reliability and lower maintenance requirements are the big (possible) benefit of a piston (that would outweigh a slight loss in accuracy) . It better place nice with PMAGS too. I have to say, I don’t like the stock design it looks to narrow at the folding point and I like a fat cheek weld. A dedicated 300 BLK piston side-folder potentially has a lot going for it. We’ll see how this pans out over the coming year or so… They are blazing some new ground here (of which for example, LWRC did not dare to tread).

  • Plumbiphilious

    Really wish the barrel was thicker myself. While it’s a piston gun (or rather, because of it), I’d like it to be more resistant to bending.

    • JQP

      Good catch. Yeah, we’ll have to see how that affects accuracy (particularly with the harmonics of a piston), and especially once it gets heated up. I think the 9″ AAC has got to be the benchmark and that puppy is thick (and damn accurate).

    • I like a thicker barrel also but I didn’t have any issues with accuracy.

      • JQP

        Darndest thing how that works sometimes…. Prime example – the Scar 17s – almost a pencil barrel profile and shoot dimes at 100 yds, even after it’s hot. So yeah, physics sometimes works in strange ways… I have lots of hopes for this platform. I’m hoping it’s a winner. They are sorta venturing where no one has gone before.

        • JQP

          (note: of course I’m aware of the PWS Mk109, but reports are that it’s a bit undergassed (wants a can at all times). and the Adams Arms XLP looks promising, but they haven’t figured out how to allow access to the adjustable gasblock with a FF rail yet. Also it’s so obscure, try getting a review or any good real world data. Hoping MCX is the one)

        • I really enjoyed shooting it. I’m kinda thinking about the pistol version.

  • chestyp

    I haven’t read through all of the comments here, so I’m not sure if anybody has mentioned this yet.

    Say what you will about Sig. Honestly, I have never been a Sig fanboy per se. We carry Sig 226KAK’s and 556 SBR’s at work. I have never been a fan of triggers on either platform.

    They are cool guns and have never had any issues, but to me, the 556 line is somewhat dated. Yes, I know, I know, the AR Platform is from 1957. The thing is, it has been updated and improved upon ever since. Excepting the recent 556xi, the sig 5– series has not undergone much change since its inception. Again, to me, no matter how smooth shooting the legacy sig pistols are, I just can’t get past the triggers vs. a good quality striker fired pistol.

    That being said, I am very impressed with what sig is doing. It seems to me that they are one of the very few firearms companies [other than Desert Tech with the MDR] who are investing lots of money into something that is not the run-of-the-mill, and proven selling AR 15/10 platform. Indeed, Sig is late to the striker-fired game with the pistols, but from what I’ve seen the P320 it is a quality design.

    The rifle’s they are developing are, to me quite the risky investment as they are somewhat cutting edge in design, especially the MCX and MPX and if they don’t catch on could cost the company plenty of cash. I’m not by any stretch an expert, but it seems like this kind of new investment is extremely good for the firearms industry.

    I for one definitely plan on picking up an MCX and hopefully an MPX sometime this year.