Sig Sauer MCX Virtus .300 AAC Blackout AR Pistol, 9 in, Coyote Tan, Short-Stroke Piston, SB Tactical Folding Brace
This Sig Sauer MCX Virtus AR pistol is a .300 AAC Blackout build with a 9 inch, cold hammer forged, threaded barrel and a short-stroke gas piston system with a 2-position adjustable gas valve. Its internal recoil system supports a true side-folding rear interface and comes outfitted with an SB Tactical brace. The upper, lower, and handguard share a uniform coyote tan finish, and the factory box label is dated 17-JUL-2023. It includes an installed two-port muzzle brake, a Magpul PMAG Gen M3 for 300 BLK, and an M-LOK QD sling socket.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This firearm shows light signs of wear and handling. A few surface scratches are visible on the metal. The finish holds up well with minimal loss.
What’s Included
- SB Tactical pistol stabilizing brace (installed, side-folding)
- One 30-round Magpul PMAG Gen M3 magazine for 300 BLK (polymer)
- M-LOK QD sling socket installed at the front left of the handguard
- Two-port muzzle brake/compensator (installed)
- SIG factory cardboard box with label (SKU PMCX-300B-9B-LT)
The MCX Virtus platform uses a short-stroke gas piston with a 2-position adjustable gas valve, delivering reliable cycling tailored to .300 BLK loads. Controls are fully ambidextrous, including the manual safety and charging handle, and the trigger is Sig’s Matchlite Duo two-stage unit.
The 9 inch barrel is cold hammer forged with a 1:5 twist and 5/8x24 muzzle threads. A two-port muzzle brake/compensator is installed. This configuration supports the caliber’s performance in a compact format while maintaining durability and service life.
An internal recoil system eliminates the need for a buffer tube and enables a true side-folding rear interface. The pistol arrives with an SB Tactical side-folding brace featuring a hook-and-loop strap for secure support.
The free-float aluminum M-LOK handguard includes enlarged gas-access windows and integral QD points, and a continuous 12 o'clock MIL-STD-1913 top rail provides uninterrupted mounting space. Furniture includes a Magpul polymer pistol grip, and the receivers and handguard share a uniform coyote tan finish. Capacity is 30+1, and the factory part number is PMCX-300B-9B-LT with a box label dated 17-JUL-2023. Made in the USA.