SIG Sauer MPX Gen 1 SBR 9mm, 8 in. Barrel, Exeter-Marked, Folding Stock, Flip-Up Sights, 3x 35-Rd Mags
This first-generation SIG Sauer MPX SBR stands out with its Exeter marking, short-stroke gas piston system, and an 8-inch threaded barrel capped with an open-prong flash hider. It features a folding skeleton stock, factory flip-up sights, and thoughtful control placement. Custom magwell engraving and an installed handstop add distinctive touches, and it comes with three 35-round Gen 1 magazines and original SIG accessories.
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 mild exterior wear and light carbon buildup from prior firing and normal function testing.
What’s Included
- SIG Sauer factory hard case
- SIG MPX manual
- SIG MPX cleaning kit in green nylon pouch
- Three 35-round SIG MPX Gen 1 polymer magazines with metal feed-lip assemblies
This MPX is a first-generation, Exeter-marked SBR built around a semi-automatic, short-stroke gas piston system with a closed rotating bolt. The 8-inch barrel is threaded and fitted with an open-prong flash hider, offering compact handling with effective muzzle flash reduction. The receiver wears a matte black anodized finish with a black overall presentation.
Controls are intuitive and fast: a non-reciprocating charging handle on the left, a right-side bolt catch/release, a right-side standard magazine release, and an ambidextrous safety selector. The folding, single-strut skeleton stock provides a 12.25-inch length of pull, and the textured polymer pistol grip offers secure purchase.
The free-floating, ventilated aluminum handguard aligns with a continuous M1913 top rail that runs across the receiver and handguard. Removable rail sections at 3, 6, and 9 o'clock allow modular accessory placement. Factory flip-up front and rear iron sights are installed for immediate usability.
Custom details include a magwell engraving featuring a coiled-snake motif and the text "SHELTON NFA TRUST, BELTON TX." An underside handstop is installed on the 6 o'clock rail for added control and indexing.
Capacity is 35+1 with the included three 35-round magazines. These are Gen 1 SIG MPX polymer magazines with metal feed-lip assemblies. Note that Gen 1 MPX magazines are unique to this generation and are not cross-compatible with later Gen 2 magazines.