The Sig Sauer M400 TREAD V2 5.56 NATO 16 in 10rd is a semi-automatic AR-style rifle built around a 16-inch stainless steel barrel and a free-floating Tread enhanced M-LOK handguard. Designed for optics-ready installation and practical use, it pairs a SIG 2-Stage Matchlite DUO trigger with ambidextrous controls and a Magpul MOE fixed carbine stock. The rifle operates on a mid-length direct impingement gas system and ships with a single 10-round polymer magazine. Its configuration favors modularity, reliable function, and straightforward range use.
| Manufacturer | Sig Sauer |
|---|---|
| Model | M400 TREAD V2 |
| Material | Stainless steel barrel, aluminum handguard and upper/lower receiver (per manufacturer specs) |
| Compatibility | .223 Rem / 5.56 NATO |
| Finish | Hardcoat anodized black receiver, stainless steel barrel |
| Weight | 7.5 lbs (per manufacturer specs) |
| Condition | New |
Key Features
- 16-inch stainless steel barrel — WHY IT MATTERS: Stainless steel resists corrosion better than chrome-moly, so this barrel stays accurate longer through humid range days or light rain. The 1:7 twist stabilizes both 55-grain plinking rounds and 77-grain match loads.
- SIG 2-Stage Matchlite DUO trigger — WHY IT MATTERS: A crisp two-stage trigger helps new shooters learn precise trigger control without the heavy pull of a mil-spec trigger. The second stage breaks cleanly around 4.5 pounds, reducing flinch and improving accuracy.
- Free-floating Tread enhanced M-LOK handguard — WHY IT MATTERS: The handguard doesn’t touch the barrel, so barrel harmonics stay consistent. That means your point of impact won’t shift when you mount a bipod, light, or vertical grip.
- Ambidextrous controls — WHY IT MATTERS: Left-handed shooters can work the safety, bolt catch, and mag release without switching hands. For family training, ambi controls mean everyone shoots the same rifle comfortably.
- Optics-ready upper receiver — WHY IT MATTERS: The receiver is pre-machined for direct-mount optics (like SIG’s own ROMEO series). No adapter plates needed, so you can mount a red dot or LPVO in minutes and get on target faster.
Who It’s For
This rifle is for families teaching new shooters, youth shooters moving up from .22 LR, and beginners who want a reliable, easy-to-use AR that won’t break the bank. The 10-round magazine makes it range-friendly in restricted states, and the fixed carbine stock simplifies length-of-pull for smaller frames.
Pros & Cons
- Pro: Excellent trigger out of the box — the Matchlite DUO is a genuine upgrade over mil-spec triggers. Many shooters report groups under 1.5 MOA at 100 yards with match ammo.
- Pro: Lightweight at 7.5 lbs — easy for smaller shooters to hold steady during prone or bench shooting.
- Con: The fixed carbine stock limits length-of-pull adjustment. Taller shooters may find the 13.5-inch pull a bit short. You can swap in an adjustable stock, but that’s an extra cost.
Comparison
| Feature | Sig Sauer M400 TREAD V2 | Zev Technologies AR-15 | Geissele Super Duty |
|---|---|---|---|
| Barrel material | Stainless steel | Chrome-moly vanadium | Chrome-moly vanadium |
| Trigger | SIG 2-Stage Matchlite DUO | Zev drop-in (single-stage) | Geissele SSA-E (two-stage) |
| Handguard | Free-float M-LOK, 15-inch | Free-float M-LOK, 15-inch | Free-float M-LOK, 15-inch |
| Weight | 7.5 lbs | 6.8 lbs | 7.2 lbs |
| Stock | Magpul MOE fixed carbine | Adjustable (Zev) | Geissele Super 42 buffer tube |
| Price | $898.64 | $1,899 | $1,999 |
The Sig M400 TREAD V2 offers a stainless barrel and premium trigger at roughly half the cost of comparable high-end builds. It’s a smart choice for families who want quality without paying for custom parts they don’t need.
FAQ
Will this rifle accept standard AR-15 magazines?
Yes, the M400 TREAD V2 uses standard AR-15/M16-pattern magazines. It ships with one 10-round polymer magazine, but you can use any capacity that’s legal in your state. Magpul PMAGs, Lancer L5AWM, and GI-style aluminum mags all work.
Is the barrel chrome-lined?
No, the barrel is stainless steel, not chrome-lined. Stainless steel offers better inherent accuracy and corrosion resistance, but it may require more careful cleaning than a chrome-lined barrel. For most range and home-defense use, stainless is an excellent choice.
Does this rifle come with iron sights?
No, the M400 TREAD V2 ships without iron sights. The upper receiver is optics-ready with a flat-top Picatinny rail, so you can mount your choice of red dot, holographic, or magnified optic. SIG recommends the ROMEO5 or ROMEO7 for a simple red dot setup.
Can I install a suppressor on this rifle?
Yes, the barrel is threaded 1/2×28, which is the standard for 5.56 muzzle devices. You can attach a muzzle brake, flash hider, or suppressor-compatible mount. Note that the handguard may not clear a suppressor if it’s over 1.5 inches in diameter — check your suppressor dimensions before mounting.
What is the gas system length?
The M400 TREAD V2 uses a mid-length direct impingement gas system. Mid-length is smoother than carbine-length, reducing felt recoil and improving reliability with a wider range of ammunition. It’s a good choice for new shooters learning to manage recoil.
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Browse more AR-style rifles in our AR Rifles category, or check out all firearms for the whole family. If you’re looking for a first AR for a young shooter, read our guide on youth shooting gear.
Last updated: April 2026
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