Sig Sauer MPX K 9mm AR Pistol, 4.5 in Barrel, Lancer Carbon-Fiber M-LOK Handguard, Aimpoint ACRO C-2, TTI Upgrades, 2x 35-Round Mags
This customized Sig Sauer MPX K stands out with a 4.5 in barrel, short-stroke gas-piston system, and premium upgrades installed throughout. It includes an Aimpoint ACRO C-2 red dot on a Reptilia mount, a Lancer Systems carbon-fiber M-LOK handguard with grip panels, a TTI flared magwell with extended basepads on two 35-round magazines, and a three-port muzzle brake. The side-folding brace and receiver Picatinny rail with a short forward section round out a compact, well-equipped 9mm package.
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: There is minimal wear and use evident, with a couple of light scuffs from handling.
What’s Included
- Aimpoint ACRO C-2 red dot sight (installed)
- Reptilia ACRO mount (installed)
- Lancer Systems carbon-fiber M-LOK handguard with textured grip panels (installed)
- Taran Tactical Innovations flared magwell (installed)
- Radian Raptor-LT ambidextrous charging handle, TTI-branded (installed)
- Three-port muzzle brake/compensator (installed)
- 2x 35-round SIG MPX-pattern polymer magazines with TTI extended basepads
- Survivor Case soft case
The MPX K configuration pairs a compact 4.5 in barrel with Sig Sauer’s short-stroke gas-piston, rotating closed-bolt operating system. The 1:10 twist barrel is optimized for 9mm Luger. The receiver has a Picatinny rail with a short forward cantilevered section, and the Lancer handguard has no top rail, so mounting space is not continuous over the handguard.
A Lancer Systems carbon-fiber M-LOK handguard is installed, offering a lightweight, rigid feel with an integrated hand-stop profile and applied grip panels. The carbon-fiber construction helps manage front-end weight while maintaining durability.
Controls and ergonomics are thoroughly addressed. An ambidextrous safety selector is standard, and a Radian Raptor-LT ambidextrous charging handle (TTI-branded) is installed for bilateral manipulation. Reloads are streamlined by a Taran Tactical Innovations flared magwell and extended magazine basepads, and the package includes two 35-round MPX-pattern polymer magazines for a 35+1 capacity.
The muzzle end features a three-port brake/compensator to help manage movement. Targeting is handled by an Aimpoint ACRO C-2 red dot sight with a red reticle, mounted on a Reptilia ACRO mount and installed to the top rail.
The aluminum-alloy receiver has an anodized finish, and the pistol is outfitted with a side-folding brace that uses a skeletonized strut for a compact footprint when stowed. The result is a refined MPX K build with practical upgrades across sighting, handling, and control surfaces.