SIG Sauer M400 TREAD 5.56 NATO AR-15 Rifle, 16 in Stainless Threaded Barrel, Mid-Length Gas, Free-Float M-LOK, Includes 3x 30-Round Magazines
This SIG Sauer M400 TREAD stands out with a 16-inch stainless steel, threaded barrel and a mid-length gas system for smooth operation. It features a free-float aluminum M-LOK TREAD handguard, a flat-top upper receiver with Picatinny rail, and factory three-prong flash hider. Made in the USA with Newington, NH markings, it comes in excellent condition and includes three 30-round magazines and the factory manual.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: The rifle is in great shape with mild evidence of handling and light use.
What’s Included
- Three 30-round polymer magazines (Magpul PMAG and Mission First Tactical models)
- SIG Sauer M400 TREAD / M400 PRO operator's manual
The M400 TREAD is built on the AR-15 platform with a direct impingement, gas-operated system. The mid-length gas setup is paired to a 16-inch stainless steel barrel with a 1:8 twist to stabilize a broad range of 5.56 NATO projectiles. The barrel is threaded 1/2x28 UNEF and fitted with the factory three-prong flash hider.
The free-float aluminum M-LOK TREAD handguard provides solid accessory mounting while keeping weight down. Its user-serviceable two-screw interface supports the TREAD accessory ecosystem. Up top, the flat-top upper receiver includes a Picatinny rail, forward assist, and ejection-port cover.
Controls and furniture are straightforward and durable, including a SIG SAUER polymer pistol grip and a 6-position adjustable, telescoping polymer stock. A manual safety selector is standard. The listed length of pull is 12.0 inches.
Receivers are aluminum with factory markings that include SIG SAUER Newington, NH and "SIGM400" on the upper. Overall length is approximately 32.6–35.8 inches, with an unloaded weight around 7.0 pounds. Capacity is 30+1 when using the included 30-round magazines.