Sig Sauer MCX-R Regulator 5.56 NATO 16" FDE — Short-Stroke Gas Piston, Ambidextrous Controls, Threaded CHF Barrel, Match Trigger
The MCX-R Regulator combines Sig Sauer's MCX short-stroke gas-piston system and internal recoil assembly with a traditional fixed-stock layout. This 5.56 NATO rifle features a 16" cold hammer-forged, threaded carbon-steel barrel with a two-port compensating brake, a free-float aluminum M-LOK handguard, and fully ambidextrous controls. Finished in Gen II NiR FDE Cerakote, it comes in excellent condition with three 10-round magazines, an installed one-piece cantilever scope mount, a detachable bipod, and an uninstalled Magpul SGA cheek riser.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This rifle has been very well maintained and cared for.
What's Included
- 3x 10-round magazines (Magpul PMAG GEN M3 and Mission First Tactical models noted)
- One-piece cantilever scope mount (installed)
- Detachable rifle bipod (loose)
- Magpul SGA cheek riser (uninstalled)
The MCX short-stroke gas-piston system with an internal recoil assembly eliminates the need for a buffer tube, enabling the proprietary MCX-R lower to pair with MCX uppers. This configuration does not include an integrated ARCA rail; support gear interfaces via the M-LOK handguard and top Picatinny rail.
The 16" carbon-steel barrel is cold hammer-forged and threaded, and it is fitted with a two-port compensating brake. A free-float aluminum M-LOK handguard and a continuous top Picatinny rail provide a solid mounting foundation, complemented by the installed one-piece cantilever scope mount.
Controls are fully ambidextrous, including the safety, magazine release, and bolt catch. The rifle uses an ambidextrous AR-style T-handle charging system and a two-stage match trigger. It feeds from AR-15/STANAG magazines and ships with three 10-round mags as noted.
The fixed polymer stock features spacer-adjustable length of pull, a cheek riser, and a rubber buttpad. The rifle wears a Gen II NiR FDE Cerakote finish over aluminum-alloy receivers and follows a traditional fixed-stock ranch rifle configuration made in the USA.