Sig Sauer MPX 9mm AR Pistol, 8" Threaded Barrel, Gear Head Works Tailhook Folding Brace, Ambidextrous Controls, KeyMod Handguard, 2x 30-Round Magazines
This customized Sig Sauer MPX 9mm pistol pairs the MPX short-stroke gas piston system with an upgraded Gear Head Works Tailhook arm brace on a left-side-folding strut. It features an 8" threaded barrel with a 1:10 twist, the MPX quick-change barrel system with twin clamping screws, and an early KeyMod free-float handguard with a full-length 12 o'clock Picatinny rail. Built on aluminum receivers in the USA, it comes ready with flip-up iron sights and two factory 30-round MPX magazines.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Condition: Good - Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling - Intact, well-defined lands and grooves.
Specific Condition Notes: There are a few minor scuffs and light finish wear in select areas. One small spot of finish wear is visible where an optic was previously mounted.
What's Included
- Brace: Gear Head Works Tailhook arm brace on side-folding strut (installed)
- Sights: Flip-up iron sights (installed)
- Muzzle Device: Three-prong flash hider (installed)
- Hand Stop: KeyMod front hand stop (installed)
- Pistol Grip: Magpul pistol grip (installed)
- Magazines: 2x 30rd SIG Sauer MPX factory polymer magazines
The MPX operating system uses a short-stroke gas piston with a closed rotating bolt, delivering smooth cycling in a compact 9mm platform. The 8" barrel is threaded and cut with a 1:10 twist, and it interfaces with the MPX quick-change barrel system secured by twin clamping screws.
This example is upgraded with a Gear Head Works Tailhook arm brace on a left-side-folding strut. It attaches via the rear 1913 Picatinny interface, allowing the brace to fold flat to the left side for compact storage and transport.
Controls are fully ambidextrous, including the magazine release, safety selector, and charging handle. The aluminum receivers and free-float aluminum handguard balance durability with manageable weight. A Magpul pistol grip provides a secure, modern grip profile.
The early-pattern free-float KeyMod handguard (pre-M-LOK) and a full-length 12 o'clock Picatinny rail run across the upper and handguard. Flip-up iron sights are installed, and a three-prong flash hider caps the threaded muzzle.
Capacity is 30+1, and this pistol includes two factory 30-round MPX magazines. Made in the USA, it brings together proven MPX engineering with practical upgrades for a refined, compact 9mm package.