Breek Arms Sentinel Closed Tine Plan B Flash Hider 30 Caliber 5 8X24 Compatible With Plan B Rearden Matte Finish Black BRK4421 UPC 812296031770
Product Description
The Breek Arms Sentinel Closed Tine Flash Hider (BRK4421) is a high-performance suppressor adapter and muzzle device purpose-built for .30 caliber rifles (.308 Win, 7.62x51mm NATO, 300 Blackout, and 6.5 Creedmoor). Designed around the popular Plan B mount standard, the Sentinel provides seamless compatibility with Q® Plan B and Rearden Manufacturing suppressor quick-detach (QD) mounting systems, offering shooters a rock-solid, concentric interface for fast suppressor attachment and removal.
Precision CNC-machined from heat-treated 17-4 PH stainless steel, the Sentinel features a closed-tine architecture that drastically reduces muzzle flash signature while eliminating the annoying ringing or "pinging" sound common to open-prong flash hiders. The closed-bottom geometry acts as a natural compensate-style force break, mitigating muzzle rise and preventing dust kickup when firing from a prone position.
Finished in a resilient, non-reflective black nitride (QPQ) coating, the BRK4421 resists heavy carbon buildup, extreme thermal cycles, and environmental corrosion. Threaded in standard 5/8"-24 UNEF right-hand pitch, this muzzle device incorporates precision taper alignment surfaces to guarantee repeatable, concentric lockup with Plan B pattern suppressor mounts, protecting against dangerous baffle strikes on suppressed tactical rifle builds.
*Armorer Bench Notes & Real-World Staging Guidance:*
Fitment Matrix: Threaded 5/8"-24 UNEF for .30 caliber / 7.62mm barrels (300 BLK, .308/7.62x51, 6.5 Creedmoor, etc.). Compatible with Q® Plan B, Rearden Atlas, and all Plan B-pattern QD suppressor mounting hubs.
- Ensure the host rifle is completely clear, magazine removed, and chamber visually and physically verified empty.
- Clean and degrease the barrel muzzle threads thoroughly using isopropyl alcohol or dedicated solvent.
- Apply a high-temperature threadlocker (Rocksett recommended for suppressor mounts) to the 5/8"-24 muzzle threads.
- Thread the Sentinel flash hider onto the barrel and torque to 25–30 ft-lbs using a dedicated muzzle device wrench applied to the wrench flats. Allow 24 hours for Rocksett to cure before mounting suppressors or firing.
Key Features
- Plan B & Rearden QD Compatibility: Precision taper-mount geometry locks up seamlessly with Q® Plan B and Rearden Atlas suppressor mounts.
- Closed Tine Flash Suppression: Effectively dampens flash signature without the ringing sounds inherent to open-prong designs.
- 17-4 PH Stainless Steel: Heat-treated stainless steel construction offers extreme thermal durability and high-pressure resilience.
- Black Nitride (QPQ) Finish: Smooth QPQ coating provides high corrosion resistance and easy carbon removal.
- Closed-Bottom Architecture: Prevents prone dust kickup while assisting with flat muzzle control during rapid firing strings.
Product Specifications
- Brand: Breek Arms
- Model/Series: Sentinel Closed Tine Flash Hider (Plan B Series)
- MPN / SKU: BRK4421
- UPC: 812296031770
- Caliber Compatibility: .30 Caliber (.308 / 7.62mm / 300 BLK / 6.5 Creedmoor)
- Thread Pitch: 5/8"-24 UNEF RH
- Mount Standard: Q® Plan B / Rearden Compatible Taper Mount
- Material: 17-4 PH Stainless Steel
- Finish/Color: Matte Black Nitride
- Country of Origin: United States
