Description
The Knights Armament 5.56mm QDSS NT4 (Black) Kit is a complete, ready-to-install suppressor package for your AR-platform rifle. It’s the iconic, military-proven sound suppressor designed for direct thread mounting, and this kit includes everything you need to get it on your gun and start shooting suppressed. I’ve run a few hundred rounds through one on a 10.5″ upper, and it delivers that classic, robust KAC performance with a simple, effective design. This isn’t the lightest or quietest can on the market today, but it’s built like a tank and represents a piece of modern firearms history you can own.
Key Features
- Complete Kit: Includes suppressor, mounting collar, wrench, and manual.
- QDSS-NT4 Design: The legendary, military-spec 5.56mm suppressor.
- Direct Thread Mount: Simple, secure attachment via a proprietary collar system.
- Full-Auto Rated: Built to handle sustained fire and hard use.
- Phosphate Finish: Durable, corrosion-resistant black exterior.
Specifications & Details
| Specification | Detail |
|---|---|
| Caliber | 5.56mm NATO / .223 Remington |
| Overall Length | Approx. 7.5 inches |
| Diameter | Approx. 1.5 inches |
| Construction | Stainless steel / Inconel internals |
| Mounting System | Knights Armament Direct Thread QD |
| Weight | Approx. 17 oz (unmounted) |
Weighing in at roughly 17 ounces, the NT4 adds some heft to your muzzle, but that weight translates directly into durability. The kit is designed to interface with the standard KAC 3-prong or 4-prong flash hiders, which you’ll need to have installed on your barrel first. The good news? It’s a true mil-spec compatible system, so if your upper is built to spec, this suppressor fits out of the box with the correct muzzle device. That means no gunsmithing required for the install, just proper timing of the flash hider. At $1429.17, you’re investing in a suppressor with a proven combat pedigree, not just a range toy.
Who This Suppressor Is For
This kit is for the shooter who values provenance and overbuilt reliability above all else. It’s for the guy building a clone-correct MK12 or M4A1, or anyone who appreciates the heritage of Knights Armament. It’s also a solid choice for someone who wants a simple, direct-thread suppressor that doesn’t rely on complex locking mechanisms. If you run a Daniel Defense or BCM rifle with a KAC muzzle device already installed, this is a logical and historically authentic upgrade. Look, it’s not for the weight-weenie or someone chasing the absolute lowest decibel rating—it’s for the person who wants a piece of gear that’s been there and done that.
Pros & Cons
Pros: Legendary military pedigree and reliability. Simple, robust direct-thread mounting. Full-auto rated for extreme durability. Comes as a complete, ready-to-go kit. The phosphate finish is tough and hides wear well.
Cons: Heavier than many modern 5.56 suppressors. Requires a specific, proprietary KAC muzzle device (not included). Sound suppression is good but not class-leading by today’s standards. The price point is an investment.
Frequently Asked Questions
Q: What muzzle device do I need to use this NT4 kit?
A: You need a Knights Armament QDSS-NT4 compatible flash hider, specifically the 3-prong or 4-prong model (part #30150 or #30151). This must be properly installed and timed on your rifle’s barrel before the suppressor can attach.
Q: Is this suppressor compatible with .300 Blackout?
A: No, it is designed specifically for 5.56mm/.223 Remington. Do not use it with .300 Blackout ammunition, especially subsonic rounds, as it is not rated for that caliber and could be dangerous.
Q: What’s the process to purchase this?
A: As a suppressor, it’s an NFA item. After selecting it, you’ll need to complete an ATF Form 4, submit fingerprints and a photo, and pay a $200 tax stamp. Once approved (a several-month wait), you can pick it up from your chosen FFL. We ship to Missouri and compliant US states to begin the process.
Ready to add a piece of special operations history to your stable? This Knights Armament 5.56mm QDSS NT4 (Black) Kit is available at firearms-missouri.com for Missouri residents and nationwide. Start the paperwork and experience that iconic KAC performance for yourself.




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