SIG Sauer MCX-Regulator 5.56 NATO Semi-Auto Rifle, 16 in CHF Barrel, FDE, Short-Stroke Piston, Ambi Controls, 10+1
This SIG Sauer MCX-Regulator stands out for its short-stroke gas piston system, cold hammer-forged 16 in carbon steel barrel, and fully ambidextrous controls. Finished in FDE with an aluminum alloy receiver, it adds a free-float aluminum M-LOK handguard and a continuous 1913 Picatinny top rail that bridges the receiver and handguard. A three-port muzzle brake is installed, and the rifle is marked with factory 5.56 NATO chambering and MCX-R multi-cal designation.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: There are a few mild scuffs from the charging handle; overall the rifle remains in great shape.
What’s Included
- Original box
- Black nylon sling (installed)
- Front and rear sights (installed)
- 1x 10-round Magpul PMAG AR/M4 GEN M3 polymer magazine marked 5.56x45
The MCX-Regulator uses SIG's MCX system with a rotating bolt and a semi-automatic, short-stroke gas piston action. This setup is designed for consistent cycling and pairs with a cold hammer-forged carbon steel barrel. The barrel is threaded and fitted with a three-port muzzle brake, and it is factory stamped "5.56 NATO."
Control layout is fully ambidextrous, including the safety selector, magazine release, and bolt catch, and it is complemented by an ambidextrous charging handle. A two-stage match trigger provides a crisp break. The rifle feeds from a 10-round magazine for a 10+1 configuration.
The aluminum alloy receiver wears an FDE finish that matches the handguard. A continuous 1913 Picatinny top rail bridges the receiver and handguard, while the free-float aluminum M-LOK handguard offers M-LOK slots at the 3, 6, and 9 o'clock positions for accessory mounting. Sights come installed.
Stock configuration is a fixed Magpul SGA with non-pistol-grip ergonomics. Length of pull is spacer-adjustable, set at 12.25 in, and the stock includes an integral sling loop and recoil pad. The rifle is made in the USA and is a recent release in the MCX-Regulator series.