SIG Sauer M400 TREAD 5.56 NATO, 16-inch Stainless, Mid-Length, Free-Float M-LOK, ROMEO5 Red Dot, 3 PMAGs
This SIG Sauer M400 TREAD stands out with its 16-inch stainless steel barrel, mid-length gas system, and a free-floating aluminum M-LOK handguard designed around the TREAD two-screw interface. It is equipped with a SIG Sauer ROMEO5 red dot on a Picatinny riser, ambidextrous controls, and comes with three 30-round Magpul PMAGs. Factory markings include an upper receiver marked "SIGM400" and a barrel marked "5.56 NATO," with manufacture by SIG SAUER Inc., Newington, NH, USA.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: There are markings and areas of surface rust on the barrel from previous handling and use. The bore is bright and clean. Please refer to the photos for a closer look.
What’s Included
- SIG Sauer M400 TREAD 5.56 NATO rifle
- SIG Sauer ROMEO5 red dot sight
- Picatinny riser mount for ROMEO5 (installed)
- SIG SAUER M-LOK vertical foregrip (installed)
- M-LOK hand stop (installed)
- Three (3) 30-round Magpul PMAG polymer magazines
The 16-inch stainless steel barrel uses a 1:8 twist to stabilize a wide range of 5.56 NATO projectiles. It is threaded 1/2x28 UNEF and capped with a SIG three-prong flash hider for muzzle device compatibility. The mid-length gas system uses a low-profile gas block to support balanced cycling.
The free-floating aluminum M-LOK handguard provides rigid accessory mounting while preserving barrel harmonics. The rifle features an ambidextrous safety selector and ambidextrous magazine catch for versatile control.
A SIG Sauer ROMEO5 red dot is installed on a Picatinny riser, delivering a clean red dot reticle for fast sighting. The receiver is an aluminum alloy construction with the upper marked "SIGM400," while the barrel is marked "5.56 NATO."
This AR-15 platform M400 TREAD includes a collapsible 6-position stock with a 10.5-inch length of pull. The package is rounded out with three 30-round Magpul PMAGs and installed M-LOK accessories, ready for range use.