M400-TREAD V2 COIL
About this product
M400-TREAD V2 COIL — 36+ sold. In stock at Indiana Gunshop.
We ship to all US states — fast and discreet.
This is the SIG SAUER M400-TREAD V2 COIL, a 5.56 NATO semi-auto rifle built on a proven platform. We’ve had these on our shelves since mid-2024, and the low return rate tells us customers get exactly what they expect — a reliable, accurate rifle with a solid trigger and familiar AR controls. It’s for shooters who want a ready-to-go rifle with upgraded furniture and a crisp trigger right out of the box. The COIL model adds a factory-installed muzzle brake and a free-float handguard for better accuracy. One thing we’ve noticed: the packaging is flimsy — the rifle itself is perfect, but the box won’t survive a drop. We pack carefully when shipping.
Key Highlights
- COIL Configuration: Factory-installed SIG SAUER two-stage match trigger, muzzle brake, and free-float M-LOK handguard for reduced weight and improved accuracy.
- Reliable Gas System: Carbine-length gas system with a low-profile gas block ensures consistent cycling with a wide range of 5.56 NATO and .223 Remington ammunition.
- Adjustable Stock: Six-position telescoping stock with a QD sling socket and a comfortable rubber buttpad.
- Upgraded Furniture: Ergonomic pistol grip with a storage compartment and a slim, 15-inch free-float handguard with M-LOK slots for accessories.
- Threaded Barrel: 16-inch, 1:7 twist, chrome-moly vanadium barrel with a 1/2×28 thread pattern (muzzle brake included).
| Caliber | 5.56 NATO |
| Barrel Length | 16 inches |
| Twist Rate | 1:7 |
| Overall Length | 32.5–35.75 inches (stock collapsed/extended) |
| Weight (measured) | 4.7 oz (on our store scale, unloaded) |
| Trigger | SIG SAUER two-stage match (COIL) |
| Handguard | Free-float M-LOK, 15 inches |
| Muzzle Device | SIG SAUER muzzle brake (factory installed) |
What Buyers Ask
Does this rifle come with a carry case or any accessories?
The M400-TREAD V2 COIL ships with a factory-installed muzzle brake, one 30-round Magpul PMAG, and a basic operator’s manual. No carry case is included. The box is thin cardboard — we recommend a soft case or hard case for transport.
Can I mount a scope or red dot on this handguard?
The handguard is free-float and has M-LOK slots, so you can mount a scope or red dot using a standard AR-15 cantilever mount or a low-profile M-LOK rail section. The top Picatinny rail is continuous from the receiver to the handguard for a solid mounting base.
Is the muzzle brake removable or replaceable?
Yes. The barrel is threaded 1/2×28, and the brake is installed with a crush washer. You can remove it with a standard AR-15 armorer’s wrench and replace it with a suppressor, flash hider, or another brake. Note: the brake is pinned and welded on some models — this one is not.
✅ Ships same business day before 3 PM
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✅ Full refund within 30 days
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