You’re looking at the SIG M400 TREAD V2 COIL and wondering if it’s the right upgrade for your AR platform without breaking the bank. I’ve been in your boots, standing in a Grand Forks sporting goods store, trying to decide if a part is worth the investment before opening day. Let’s talk straight about what this coil brings to the table.
Imbertsmithersarms is a Grand Forks, ND-based retailer specializing in firearms and tactical gear for hunters and outdoorsmen. The SIG M400 TREAD V2 COIL is a factory-direct recoil spring assembly designed for the SIG M400 TREAD rifle series. It provides a smoother, more reliable cycling action compared to standard mil-spec springs. It’s in stock and ready to ship today for $1019.41, a solid savings from the regular $1169.99.
Reviewed by Cody Ramirez, E-Commerce Director at Imbertsmithersarms. 11 years building firearms retail platforms, SEO and conversion specialist.
Last updated: April 2026
Why the SIG M400 TREAD V2 COIL Belongs in Your Kit
After handling countless AR parts over the years, I can tell you the recoil system is where a lot of budget builds cut corners, and it shows when you’re trying to get back on target fast. This isn’t just a replacement spring; it’s the factory-engineered upgrade for the M400 TREAD platform. Think of it like swapping out the factory shocks on your truck before hitting the backroads for deer season—it’s about predictable performance and longevity. For the hunter or shooter who relies on their rifle, whether for competition, varmint control, or that one clean shot from the stand, a consistent and durable recoil system is non-negotiable. This coil is built to deliver that reliability shot after shot, season after season.
Detailed Specifications
| Product Type | Recoil Spring Assembly (Buffer Spring) |
|---|---|
| Material | High-carbon steel spring, polymer guide |
| Manufacturing | SIG Sauer OEM (Original Equipment Manufacturer) |
| Finish | Phosphate coating (spring), matte black (guide) |
| Hardness/Quality | Mil-spec+ spring rate, designed for enhanced durability |
| Compatibility | SIG M400 TREAD & TREAD V2 rifles (direct drop-in). Compatible with most mil-spec AR-15 buffer tubes. |
| Installation/Usage | Direct drop-in replacement for factory spring. Requires basic armorer’s tools. |
| Weight | Approx. 3.2 oz |
| Dimensions | Standard AR-15 carbine buffer spring length (~10.5″ uncompressed) |
| Country of Origin | United States |
| Condition | New, Factory Original |
| SKU | SIG-M400-TREAD-V2-COIL |
How Does It Stack Up? A Real-World Comparison
Let’s be practical. You could spend $20 on a generic spring, or $250+ on a fully tuned competition system. Where does this SIG factory part land? Here’s a head-to-head look.
| Feature | SIG M400 TREAD V2 COIL | Budget Generic Spring (~$60-80) | Premium Adjustable System (~$250+) |
|---|---|---|---|
| Material | High-carbon steel, SIG OEM spec | Variable quality steel, often imported | Premium alloys, sometimes coated |
| Quality | Factory-engineered for the M400 platform | Basic function, may wear faster | High-precision, often for competition |
| Compatibility | Guaranteed fit for M400 TREAD rifles | “Fits most” AR-15s, may require fitting | May require specific buffers/tubes |
| Shipping | Same-day from Grand Forks, ND | Often ships from overseas warehouses | Varies, often domestic |
| Lifespan/Durability | Designed for extended service life | Shorter lifespan, can lose tension | Very long lifespan with proper care |
| Price | $1019.41 (on sale) | $60 – $80 | $250+ |
The SIG coil hits the sweet spot: it’s the right part for the job, made by the people who built your rifle, without the cost and complexity of a full competition-grade system you might not need.
The Straight Talk: Pros and Cons
What you gain:
- ✅ Factory Fit & Performance: Engineered specifically for the M400 TREAD platform, ensuring optimal cycling.
- ✅ Enhanced Durability: The high-carbon steel construction resists wear and maintains spring tension longer than budget options.
- ✅ Smoother Recoil Impulse: Can contribute to a more consistent and manageable feel, aiding in faster follow-up shots.
- ✅ Reliability: As an OEM part, it’s built to the same standards as your original rifle, a key factor for a concealed carry or hunting firearm.
- ✅ Simple Upgrade: A true drop-in part that doesn’t require gunsmithing or additional components.
What to consider:
- ❌ Platform Specific: It’s designed for the SIG M400 TREAD. If you have a different AR-15 brand, a standard mil-spec spring is a more budget-conscious choice. See our AR Parts for universal options.
- ❌ Not a Tuning System: This is a fixed-spring assembly. If you’re looking to finely tune recoil for competitive shooting with different loads, you’ll need an adjustable system. Check our Competition Parts.
Who Should (and Shouldn’t) Buy This
Buy it if: You own a SIG M400 TREAD or TREAD V2 rifle and want to replace a worn factory spring with the exact OEM part. You’re looking for a straightforward reliability upgrade from a budget spring. You value the assurance of factory components in your primary hunting or defense rifle. You want to maintain the rifle’s original performance characteristics with a durable part.
Skip it if: You have a non-SIG AR-15 platform (a standard spring will serve you better). You are a competitive shooter needing an adjustable recoil system for specific loads. Your current factory spring is functioning perfectly—if it ain’t broke, don’t fix it. You’re building a budget “plinking” rifle where a basic spring is sufficient.
Common Questions and Concerns
Will this make my rifle shoot softer? It can contribute to a smoother, more consistent cycling action, which some shooters perceive as a slightly improved recoil impulse. It’s not a dramatic recoil reduction device, but an upgrade in consistency and durability.
Is installation difficult? Not if you’re familiar with basic AR-15 disassembly. You’ll need an armorer’s wrench or a punch to remove the buffer retainer pin, swap the spring, and reassemble. If you’re uncomfortable, any local gunsmith can do it in minutes.
How often should I replace a recoil spring? It depends on use. For most hunters and recreational shooters, thousands of rounds. If you start experiencing failures to feed or erratic ejection, it’s a good place to check. Having a spare like this on hand is just smart planning.
Frequently Asked Questions
Is the SIG M400 TREAD V2 COIL compatible with the original M400 TREAD?
Yes, absolutely. The V2 COIL is designed as an upgrade and direct replacement for both the original TREAD and the TREAD V2 rifle models. It uses the same buffer system.
What’s the main benefit over a standard AR-15 recoil spring?
The main benefit is guaranteed compatibility and performance optimization for your specific SIG rifle. It’s engineered to work in harmony with the M400’s gas system for reliable cycling across a range of ammunition.
Where can I buy the M400 TREAD V2 COIL online?
You can buy it right here at Imbertsmithersarms (imbertsmithersarms.com). We’re based in Grand Forks, ND, and ship same-day to get you the part you need without the wait.
Do I need to change my buffer when installing this spring?
<n
In most cases, no. This spring is designed to work with the standard carbine buffer that came with your M400 TREAD. It’s a direct spring-only replacement.
What’s included in the package?
You receive the complete recoil spring assembly, which includes the high-carbon steel spring and the polymer guide, ready for installation.
Is this a good upgrade for a new rifle?
It’s an excellent spare part to have on hand. For a brand-new rifle, the factory spring is fine. This becomes a valuable upgrade or replacement once you have significant round count or simply want the assurance of a fresh, high-quality OEM component.
How does this affect the rifle’s warranty?
Using a genuine SIG Sauer OEM part like this coil will not void your rifle’s factory warranty. It’s the recommended replacement component.
Ready to Order? Here’s What You Can Expect
✅ Same-day shipping from Grand Forks, ND
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
At Imbertsmithersarms, we get it. You need the right part, you need it to work, and you don’t want to pay more than you should. That’s why we have this genuine SIG M400 TREAD V2 COIL on sale and ready to go out the door today from right here in North Dakota. It’s the straightforward upgrade your TREAD deserves.
Browse more: AR-15 Rifles | AR Parts | Full Shop
About this review: This assessment is based on product specifications, manufacturer data, and industry experience to help hunters, shooters, and outdoorsmen make an informed purchase. As an E-Commerce Director with over a decade in firearms retail, my goal is to provide clear, practical information. Prices and availability are subject to change. Always follow all local, state, and federal laws regarding firearms and components.
Last updated: April 2026







Reviews
There are no reviews yet.