M400-TREAD V2 COIL
About this product
M400-TREAD V2 COIL — 79+ sold. In stock at P80Kit.
The M400-TREAD V2 COIL is a precision-engineered recoil spring assembly designed for the SIG M400 TREAD platform. It’s built for shooters seeking enhanced reliability and a smoother, more consistent cycling action. Since arriving on our shelves in late 2024, this coil has shown exceptional durability with a near-zero return rate, confirming it delivers exactly the performance shooters expect.
Why This One?
- Enhanced Reliability: Engineered to provide consistent spring tension and reduce the chance of binding, ensuring dependable function across a wide range of ammunition.
- Direct Drop-In Fit: Designed as a direct replacement for the factory M400 TREAD recoil spring assembly. No gunsmithing or modification required.
- Durable Construction: Manufactured from high-grade spring steel and finished to resist corrosion, built for long-term service life.
- Smoother Cycling: The V2 design refines the spring’s action to help reduce perceived recoil impulse and improve overall shot-to-shot consistency.
- Proven Track Record: In over a year of sales, we have had zero warranty claims submitted for this product, a testament to its build quality.
Full Spec Sheet
| Compatibility | SIG M400 TREAD / M400 TREAD II |
| Type | Recoil Spring Assembly (Buffer Spring) |
| Application | Direct Replacement / Upgrade |
| Finish | Phosphate / Anti-Corrosion Coating |
| Weight (measured) | 1.8 oz |
| Installation | Drop-In, No Modification |
| Packaging | Individual Protective Sleeve |
Q & A
Is this compatible with the original M400 TREAD and the TREAD II?
Yes. The M400-TREAD V2 COIL is designed as a direct replacement for the recoil spring assembly in both the original SIG M400 TREAD and the newer M400 TREAD II models.
Will this spring work with a carbine-length buffer tube?
Yes. This assembly is designed for use with standard carbine-length receiver extension (buffer) tubes, which is the standard configuration for the M400 TREAD series.
Does this require any special tools for installation?
No. Installation requires only standard AR-15 armorer’s tools: a castle nut wrench to remove the buffer tube if needed, and a punch to drive out the buffer retainer pin. The coil itself is a simple drop-in component once the buffer and old spring are removed.
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Specs at a glance
What's in the box
- M400-TREAD V2 COIL