Sig Sauer MPX PSB 9mm Pistol – 8" Threaded Barrel, Folding Brace, 9x 30-Round Mags
This customized Sig Sauer MPX PSB pairs the proven MPX short-stroke gas piston system with a Lage Mfg. PSB1 left-side folding brace adapter, giving the shooter a compact, highly controllable 9mm platform. An early-generation 8-inch pistol with a discontinued KeyMod handguard, it retains ambidextrous controls, a monolithic upper with full-length 1913 rail, and a threaded barrel for suppressor or muzzle device use. Complete with nine proprietary translucent magazines and a dedicated MPX backpack, this package offers a ready-to-run setup for range or defensive roles.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Condition: Excellent – clean, mirror finish, with sharp lands and grooves.
Specific Condition Notes: Only a few minor surface scratches and small blemishes are present on the exterior. The bore is bright and shiny.
What’s Included
- Sig Sauer soft MPX carry backpack
- Nine 30-round translucent polymer Sig Sauer MPX magazines
- Nylon triple MPX magazine pouches
- KeyMod rail adapter segments (installed)
- Blast can muzzle attachment (not installed)
- Sig Sauer MPX owner’s manual & safety instructions
The MPX uses a short-stroke gas piston system uncommon in pistol-caliber firearms, keeping the action clean and ensuring reliable cycling across a wide range of 9mm loads.
An 8-inch cold-hammer-forged barrel is threaded M13.5x1 LH and arrives with a removable blast can, giving the owner immediate options for suppressor installation or alternative muzzle devices.
The Lage Mfg. PSB1 adapter moves the factory PSB brace to a left-side folding configuration. The hinge locks solidly when deployed and folds flat for transport without interfering with the controls.
A monolithic upper receiver with an uninterrupted 1913 Picatinny top rail allows easy mounting of optics, lights, or other accessories. The early KeyMod free-float handguard keeps weight down while providing adequate attachment points via the included adapter segments.
Fully ambidextrous safety levers, magazine release, and bolt catch make the MPX intuitive for both right- and left-handed shooters. Captive charging handle and polymer flip-up sights round out a controls package designed for fast handling.