Sig Sauer MPX SBR 9mm, 8-inch Threaded Barrel, Timney Trigger, Sightmark Ultra Shot M-SPEC
This Sig Sauer MPX SBR stands out with an 8-inch threaded barrel, a short-stroke gas piston system with an auto-regulating gas valve, and fully ambidextrous AR-style controls. It is upgraded with a Timney drop-in trigger and includes a Sightmark Ultra Shot M-SPEC reflex sight. The side-folding, telescoping stock adds compact versatility. This is an NFA item and will require a tax stamp for transfer.
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 blemishes are present, with noticeable blemishing on the magwell.
What’s Included
- Sightmark Ultra Shot M-SPEC reflex sight (installed)
- Flip-up iron sights (front and rear) installed
- Two 35-round MPX-pattern polymer magazines with steel feed lips
The MPX SBR uses a closed, rotating bolt and a short-stroke gas piston with an auto-regulating gas valve to deliver consistent performance with 9mm ammunition. Its 8-inch barrel is threaded and fitted with a birdcage flash hider, and the 1:10 twist supports a broad range of 9mm loads.
Controls are fully ambidextrous, including the selector, magazine release, and bolt catch. The stock mounts to a rear 1913 interface and both folds and telescopes, with a QD sling socket and an 11–13 inch length of pull. The receiver is aluminum alloy and made in the USA.
A continuous MIL-STD-1913 top Picatinny rail runs from receiver to handguard for uninterrupted mounting space. The tubular aluminum handguard features diagonal ventilation slots and bolt-on Picatinny sections at 3, 6, and 9 o'clock. Flip-up iron sights are installed, and a Sightmark Ultra Shot M-SPEC reflex sight is mounted for a ready-to-use sighting setup.
This example is custom-upgraded with a Timney drop-in trigger for a refined pull. It feeds from proprietary MPX-pattern magazines and has a capacity of 35+1 with the included 35-round magazines.