SIG Sauer M400 TREAD Snakebite SE 5.56 NATO AR-15, 16 in Stainless Barrel, 1:7 Twist, Mid-Length Gas, Coyote/FDE
The M400 TREAD Snakebite SE is a distinct, factory-configured AR-15 variant announced in 2021, built around a 16 in stainless barrel with 1:7 twist and a mid-length gas system. It features a free-float M-LOK TREAD handguard, a two-stage Matchlite trigger, a threaded muzzle with a hybrid flash hider/compensator, and a durable two-tone coyote/FDE Cerakote finish. Made in the USA and receiver-marked Newington, NH, this rifle includes a Magpul MOE SL-K collapsible stock and comes with a 30-round PMAG and an installed Magpul M-LOK AFG.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Condition: Good - Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling - Intact, well-defined lands and grooves.
Specific Condition Notes: Exterior surfaces show scattered scratches and blemishes. The bore presents a bright, reflective interior.
What’s Included
- Magpul M-LOK AFG angled foregrip (installed)
- One 30-round Magpul PMAG Gen M2 MOE polymer AR-15 magazine
The Snakebite SE configuration pairs a 16 in stainless steel barrel (stamped "5.56 NATO 1/7") with a mid-length gas system for balanced cycling. The barrel is threaded 1/2x28 and fitted with a hybrid flash hider/compensator for effective muzzle device compatibility straight from the factory.
Its free-float aluminum M-LOK TREAD handguard integrates a T-numbered, flat-top Picatinny rail for mounting. The rifle ships without sights, giving the user a clean top rail to configure as desired.
Controls and handling are enhanced by SIG’s two-stage Matchlite trigger and the Magpul MOE SL-K collapsible stock, delivering an adjustable length of pull of approximately 10.5–14 in. A SIG SAUER branded polymer pistol grip and the installed Magpul M-LOK AFG round out the ergonomic setup.
The upper and lower receivers are aluminum alloy with a durable two-tone Cerakote finish: coyote on the receivers and barrel contrasted by a darker handguard. The receiver is marked "SIG SAUER INC NEWINGTON, NH, USA," reflecting its U.S. manufacture.
Chambered in 5.56mm NATO with a 30+1 capacity, this M400-series rifle retains the familiar AR-15 platform architecture while incorporating the Snakebite SE’s factory-selected components and finishes.