Knights Armament Sr-15 Ks-1 5.56 Nato 13.7'' Bbl Assembled Upper Rcvr Black

The Knights Armament SR-15 KS-1 upper receiver is a precision-engineered 5.56 NATO upper assembly built for shooters who demand suppressor-ready performance without sacrificing velocity or durability. This assembled upper features a 13.7" cold hammer-forged barrel with a 1:7" twist rate and chrome lining—a combination designed to handle both standard and suppressed fire while maintaining exceptional accuracy across extended shooting sessions.

What sets the KS-1 apart is its heavy-profile, ball-mill dimpled barrel design. Unlike traditional fluting, the dimpling process reduces weight while minimizing heat-induced point-of-impact shift—a real advantage when running suppressed or during prolonged range days. The 13.7" length with a compact suppressor mounted delivers the ballistic performance and muzzle velocity of a longer barrel in a package that handles like a 10.3" setup. If you're building a suppressed rifle that needs to stay fast and consistent, this upper delivers.

Knights Armament's reputation in precision small arms carries through every detail here. The assembly is ready to marry to a compatible lower receiver, making it ideal for builders who want to skip the barrel installation and headspace work and get straight to the range. The SR-15 platform has earned respect among serious shooters—LEO, military, and civilian operators alike—for reliability and accuracy. Whether you're running subsonic or supersonic loads, suppressed or open, this upper is built to perform.

Key Features

• Cold hammer-forged, chrome-lined barrel resists heat-induced accuracy shifts during sustained fire
• Ball-mill dimpled heavy profile reduces weight while maintaining rigidity and consistency
• 1:7" twist rate handles the full range of 5.56 NATO ammunition reliably
• Suppressor-ready design delivers full velocity and handling with compact cans
• Fully assembled upper receiver—no barrel work required

Specifications

Frequently Asked Questions

Will this upper work with my lower receiver?

The SR-15 KS-1 is an assembled upper receiver that mates to a compatible 5.56 NATO lower. Confirm your lower is in 5.56 NATO and built to AR-15 or SR-15 specs. Knights Armament uppers are engineered for SR-15 compatibility, but verify with your lower's manufacturer if you're uncertain.

Is this upper set up for a suppressor?

Yes. The 13.7" barrel is optimized for suppressor mounting, delivering rifle-velocity performance in a compact package. With a suppressor attached, it handles like a shorter barrel while maintaining ballistic efficiency. You'll still need a compatible muzzle device and suppressor.

What ammunition works in this barrel?

The 1:7" twist and 5.56 NATO chamber handle the full range of 5.56 NATO and .223 Remington ammunition. The heavy barrel is built for sustained accuracy, so it performs well across supersonic and subsonic loads.

Does this come fully assembled and ready to shoot?

The upper receiver is fully assembled—barrel, bolt carrier group, and receiver are ready to install on a compatible lower. You'll still need a lower receiver and standard components to complete the rifle.