Ronin Arms™ RA9SD 5.75″ Ported K Barrel

Compact SD Performance — Refined to Ronin Arms™ Standards

The Ronin Arms™ 5.75″ SD Ported K Barrel has been refined to our proprietary specifications to deliver the level of performance, reliability, and consistency expected from every Ronin Arms™ SD system. Rather than accepting an off-the-shelf design, we optimized the port geometry, internal dimensions, and overall gas management characteristics to meet our exact standards.

Every modification was made with one goal in mind—creating a compact SD barrel that delivers consistent gas bleed, reliable velocity reduction, and smooth, predictable suppression while maintaining excellent accuracy and long-term durability.

The result is a compact SD system that performs as intended with common 115 and 124-grain ammunition, providing the smooth shooting characteristics, reliable function, and exceptional suppression Ronin Arms™ is known for.

Purpose-Built Porting, Designed as a System

Every aspect of this barrel was engineered to work in harmony with Ronin Arms™ suppressor architecture.

Precisely calculated port geometry ensures consistent velocity reduction, controlled gas management maintains reliable cycling, reduced pressure spikes minimize unnecessary back-pressure, exact suppressor alignment guarantees proper seating, and the design supports long-term durability under hard use.

This is not a universal or adaptable component — it is a precision SD barrel, built to function as part of a complete Ronin Arms™ system.

Engineered for the Ronin Arms™ AR9 Platform

Purpose-built for true SD operation, optimized for compact K-length configurations, designed to convert standard 115gr and 124gr ammunition into subsonic at the muzzle, and balanced to reduce excess back-pressure while maintaining reliability.

This barrel is intended for shooters who value quiet efficiency and correct system design — not shortcuts.

Key Features

✔ 5.75″ SD K-length barrel engineered for compact suppressed systems
✔ Proprietary porting geometry
✔ Optimized gas regulation for smooth SD performance
✔ Precision-machined for exact suppressor alignment and seating
✔ Designed exclusively for the Ronin Arms™ AR9 platform
✔ Built for accuracy, durability, and high round-count reliability

Compatibility Notice

⚠ This barrel is designed to be paired with Ronin Arms™ suppressors 

K-length and full-size suppressors are NOT interchangeable, incorrect pairing will result in improper seating and performance failures, and this precision SD system requires correctly matched components.

If you have questions regarding suppressor compatibility, please contact us before installation.

Safety & Usage Guidelines

Suppressor Required: Do not fire without a properly paired Ronin Arms™ suppressor installed.

Correct Pairing Is Mandatory: K and full-size suppressors are not interchangeable.

Legal Compliance: Always follow all federal, state, and local regulations.

Built Different — Because It Is

The SD 5.75″ Ported K Barrel exists for one purpose: delivering refined, compact SD performance the way it was always meant to be done.

“Accept No Imitations. One Gun. One Gunsmith.”™