Sig Sauer M400 SDI X-Series AR-15 Pistol, 5.56 NATO, 11.5 in Threaded Barrel, Primary Arms Micro Red Dot, Folding Sights, 30+1
This Sig Sauer M400 SDI X-Series AR-15 pistol stands out with its 11.5-inch threaded barrel, free-float M-LOK handguard, and ambidextrous safety selector. It arrives with a Primary Arms Micro Red Dot Gen II (MD-RB011) installed and folding backup sights, and it is in excellent condition with a clean, mirror-bright bore.
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: The bore is clean and in excellent condition. Please refer to the photos for additional views.
What's Included
- Optic: Primary Arms Micro Red Dot Gen II (MD-RB011), installed
- Sights: Folding front and rear backup iron sights, installed
- 1x 30-round Magpul PMAG windowed polymer magazine
The M400 SDI X-Series pairs a direct-impingement operating system with an 11.5-inch threaded barrel capped by an open-ended three-prong flash hider with three long longitudinal slots and small radial holes near the base. A low-profile gas block and free-float aluminum M-LOK handguard with a full-length, T-marked Picatinny top rail support compact handling and accessory mounting.
Controls are set up for practical use, including an ambidextrous safety selector and a standard right-side magazine release. The pistol features a brace, SIG SAUER polymer pistol grip, and the classic AR-15 forward assist and dust cover. Receivers are aluminum with a black finish.
Factory markings include an upper marked "SIG SAUER M400 SDI" with a prominent "X," and a lower marked "SIG SAUER INC NEWINGTON NH USA" and "MULTI-CAL." The manufacturer part number is PM400-SDI-11B-BLK. Stated capacity is 30+1.
A Primary Arms Micro Red Dot Gen II (MD-RB011) is already mounted, complemented by folding backup iron sights. The full-length Picatinny rail provides straightforward placement for the optic and other accessories as desired.
Made in the USA, this X-Series pistol lists with an MSRP of $1,649.99.