SIG Sauer introduced its new modular carbine platform, the MCX, which will be available to the commercial market in semi-automatic rifle, short-barrel rifle and pistol variants. All three configurations will be available in .300 Blackout, 5.56x45 mm NATO and 7.62x39 mm, with caliber conversions available immediately. Converting from one chambering to another can be performed easily by the user in the field, as switching between .300 Blackout and 5.56 NATO requires only that the barrels and operating rods to be swapped out, and converting to or from 7.62x39 mm simply involves an additional bolt face change. The MCX shares several features with the AR-15, and indeed, the MCX’s upper is compatible with mil-spec AR lowers, however, SIG’s new gun does not require a buffer tube, allowing for the utilization of side-folding stocks. Designed from the ground up for optimal performance with the .300 Blackout cartridge through a silencer, the MCX can run supersonic on the silenced setting without damaging the firearm or negatively effecting function. The rifle configuration will sport a 16” cold-hammer-forged barrel, while both the SBR and pistol variants will feature a 9” barrel.