SIG Sauer MPX K 9mm Pistol, FDE, 4.5-inch Threaded Barrel, KeyMod Handguard, Collapsible Dual-Rod Brace, 3x 30-Round Mags
This SIG Sauer MPX K pairs the compact 9mm platform with a Flat Dark Earth finish and a feature-rich setup. It uses a closed-bolt, short-stroke gas piston system, includes a 4.5-inch threaded barrel with a multi-prong muzzle device installed, and comes with ambidextrous controls. Notable touches include the K-length aluminum KeyMod handguard with a low-profile hand stop, a collapsible dual-rod brace, a Magpul polymer pistol grip, and a folding rear sight. The original factory box and manual are included, along with three 30-round MPX-pattern magazines. The carton label is dated 22-SEP-2017 and is serial-matched to the receiver.
This example represents the earlier KeyMod handguard generation that predates later M-LOK updates. It features an AR-style charging handle and manual of arms, a continuous full-length top Picatinny rail, and accepts SIG MPX-pattern magazines. With its compact K configuration and 30+1 capacity, it delivers a capable package in a distinctive FDE finish.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: Minor surface scratches and small blemishes are visible on close inspection. Exterior finish presents evenly with crisp overall appearance.
What’s Included
- SIG Sauer factory cardboard box (original)
- SIG MPX owner’s manual
- 3x 30-round SIG MPX-pattern polymer magazines
- Folding rear sight (installed)
- Low-profile hand stop (installed on the handguard)
- Multi-prong muzzle device (installed)
The MPX K’s short-stroke gas piston system gives this compact 9mm a smooth, reliable operating cycle. It retains AR-style ergonomics with an AR-style charging handle and manual of arms, and it adds ambidextrous controls including the safety selector and magazine release, plus a left-side bolt catch.
The 4.5-inch barrel is threaded and capped with a multi-prong muzzle device. A 1:10 twist supports common 9mm loads, and the platform accepts SIG MPX-pattern magazines; capacity is 30+1. The continuous full-length top Picatinny rail provides uninterrupted mounting space.
Furniture and controls are purpose-built for compact handling: a collapsible dual-rod brace, K-length aluminum KeyMod handguard with a low-profile hand stop, and a Magpul polymer pistol grip. A folding rear sight is installed for immediate use.
This is the KeyMod-handguard generation that predates later M-LOK MPX K updates. Finished in Flat Dark Earth, it carries the U.S.-made MPN MPX-K-9-KM-FDE. The original carton label is dated 22-SEP-2017 and is serial-matched to the receiver, and the package includes the factory box, owner’s manual, and three 30-round magazines.