Sig Sauer MCX AR Pistol With Pistol Stabilizing Brace (300 BLK)

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Engineered from the ground up to be short, light, and silenced, the SIG MCX features an innovative auto-regulating or two position, short-stroke gas piston operating system. Users can change barrels, calibers, stocks, and handguards in the field.


Unlike every other firearm on the market, the SIG MCX was built for optimum performance with the 300BLK cartridge and a suppressor. The outcome is a firearm with superior suppression capability and enhanced reliability with both supersonic and subsonic loads A two-position gas block makes the transition from subsonic to supersonic as fast as flipping the lever. Changing between 300BLK and 5.56 NATO is as simple as swapping barrels and magazines in a matter of minutes. Converting to 7.62x39mm simply requires barrel, magazine, as well as an additional bolt change. Each SIG MCX features an aluminum KeyMod handguard, AR-style lower controls and utilizes standard STANAG magazines. A revolutionary recoil system does not require a buffer tube, allowing the side-folding Pistol Stabilizing Brace. A picatinny top rail allows for the mounting of lights or optics. The aluminum forend allows for rail sections to be added where they are needed, permitting the attachment of accessories. The lower receiver offers familiar AR-style controls. Completely ambidextrous controls include the safety, magazine release and charging handle.


Side-Folding Pistol Stabilizing Brace
This revolutionary brace offers maximum flexibility and improved single-handed shooting performance.


User-Changeable Barrel with 3-Prong Flash Hider
Choose from 16-inch 5.56 NATO, 300BLK and 7.62×39 barrels offering in-field adaptability. Reducing your signature, a 3-prong flash hider comes standard.


Additional Information
Manufacturer Sig Sauer
Model MCX w/Pistol Stabilizing Brace
Type Pistol:  Semi-Auto
Caliber 300 BLACKOUT/300 Whisper
Action Gas Operated Semi-Auto
Capacity 30+1
Sights No Sights
Barrel Length 9.0″
Overall Length 26″
Weight 7.2 lbs
Accessories Sig SBX Stabilizing Brace, One 30-Round Steel Magazine
UPC Product Code 798681567560
Manufacturer SKU PMCX-300B-9B-PSB

Additional Information Content

Modern Warriors

We started Modern Warriors and Alice Firearms for the sole purpose of providing a less expensive way to enjoy our love of buying and shooting some really cool stuff. What started as a hobby has turned into a business where we have developed the experience and ability to help you enjoy our same hobby and save you money in the process.

We specialize in tactical weapons, including suppressors, short barrel rifles and full auto weapons. We have routine experience in shooting the weapons we carry, so if you want our opinion on how a weapon operates, we will gladly provide it. We also have expertise working with licensed professionals in setting up gun trusts, which is an ideal way of purchasing, owning and operating any weapon restricted by the National Firearm Act. Don’t let the word “trust” scare you. It is very easy to set one up if you have the right help.

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