We've known for some time now about the MCX (Mission Configurable Weapon System) thanks to Sig's Instagram account. Sig Sauer is making it more official now though and we're seeing a lot of information become available. For those familiar with Sig's 556 line, the MCX is much like an evolution to that line. The 556 requires a proprietary lower (and the upper is serialized instead of the lower) but it is a short stroke piston system. The advantage to the MCX is that it will run on a regular AR-15 lower.
The MCX has an ambidextrous safety, mag release, and charging handle.
The MCX is designed to allow quick caliber changes between 5.56mm, .300 Blackout, and 7.62x39 (requires a different bolt as well). The MCX has a short stroke auto regulating gas operating system, modular rail system, and uses a standard AR magazine. It also has a nickel boron bolt and bolt carrier.
Sig will offer Caliber X-Change kits for swapping between calibers of MCX rifles and pistols. Based on what we are seeing, the pistol will only be offered with a PSB kit pre-installed. Judging by the photos the PSB /adapter doesn't side fold.
Below are the MCX models slated for release in 2015. We don't yet have info on availablility or pricing of the MCX Caliber X-Change Kits.
MCX Rifles
| Part Number | Description | MSRP |
| RMCX-300B-16B-TFSAL-P-CKIT | SIGMCX, 300BLK, Rifle, 16in bbl, Patrol, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, 5.56mm Cal-X Kit Included, Poly Hard Case | $2,132.00 |
| RMCX-16B-TFSAL-P | SIGMCX, 5.56 NATO, Rifle, 16in bbl, Patrol, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $1,866.00 |
| RMCX-300B-16B-TFSAL-P | SIGMCX, 300BLK, Rifle, 16in bbl, Patrol, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $1,866.00 |
| RMCX-762R-16B-TFSAL-P | SIGMCX, 7.62X39mm, Rifle, 16in bbl, Patrol, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $1,866.00 |
MCX Pistols
| Part Number | Description | MSRP |
| PMCX-300B-9B-AL-PSB-CKIT | SIGMCX, 300BLK, Pistol, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding SBX(1) 30rd Alum Mag, Alum HGD, 5.56mm Cal-X Kit Included, Poly Hard Case | $2,399.00 |
| PMCX-9B-AL-PSB | SIGMCX, 5.56 NATO, Pistol, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding SBX(1) 30rd Alum Mag, Alum HGD, | $2,132.00 |
| PMCX-300B-9B-AL-PSB | SIGMCX, 300BLK, Pistol, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding SBX(1) 30rd Alum Mag, Alum HGD, | $2,132.00 |
| PMCX-762R-9B-AL-PSB | SIGMCX, 7.62X39mm, Pistol, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding SBX(1) 30rd Alum Mag, Alum HGD, | $2,132.00 |
MCX Short Barrel Rifles (SBR's)
| Part Number | Description | MSRP |
| RMCX-9B-PDW-TFSCF-SBR | SIGMCX, 5.56 NATO, SBR, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, CF HGD, | $2,239.00 |
| RMCX-9B-PDW-TFSAL-SBR | SIGMCX, 5.56 NATO, SBR, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $2,058.00 |
| RMCX-300B-9B-PDW-TFSAL-SBR | SIGMCX, 300BLK, SBR, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $2,058.00 |
| RMCX-762R-9B-PDW-TFSAL-SBR | SIGMCX, 7.62X39mm, SBR, 9in bbl, PDW, BLK, Semi-Auto, Folding Sights, Folding Stock, (1) 30rd Alum Mag, Alum HGD, | $2,058.00 |
Recoil Magazine has a full breakdown of the MCX on their website. The above photo is from Recoilweb.com.