The Breek Arms Sentinel caged flash hider (brand part no. BRK4420) is the closed-tine member of the Plan B muzzle device family, built for .223/5.56 barrels with 1/2×28 muzzle threads. Where an open-prong flash hider can catch on slings and gear, Breek Arms shrouds the Sentinel’s tines in a full cage, so it slides in and out of a bag or a vehicle without snagging while still breaking up muzzle flash. It is machined from 4140 steel, hardened and nitride finished, and it carries the Plan B interface that lets a Plan B suppressor mount attach quickly and repeatably over the device. Breek Arms designed it for compact length and an NVG-friendly signature, which suits a duty carbine or a night-hunting rifle that runs with and without a can. For a shooter who wants one host-side device that serves as flash hider and suppressor mount, the Sentinel is the caged option.

Key Specifications

• It fits .223/5.56 barrels, the caliber the Sentinel is bored and rated for.
• The muzzle thread is 1/2×28, the standard pitch on AR-15 barrels in this caliber.
• It is a closed-tine, fully shrouded flash hider, so the tines are protected and cannot snag gear.
• The material is 4140 hardened steel, chosen for strength under repeated muzzle blast.
• The finish is nitride, which hardens the surface and resists corrosion and carbon buildup.
• Overall length is 2.15 inches, keeping the device compact on a short barrel.
• Weight is 2.2 ounces, light enough to leave the rifle’s balance alone.
• It fast-attaches Plan B suppressor mounts, so a suppressor can go on and off without unthreading the device.
• The design gives rock-solid alignment for the mounted suppressor, which protects the baffles from a strike.
• Breek Arms rates it for NVG-friendly signature reduction, a real advantage under night vision.

Frequently Asked Questions

How is the Sentinel different from the Scorch? The Scorch is Breek Arms’ open three-prong Plan B flash hider. The Sentinel closes the tines inside a full cage so the device cannot catch on gear, while keeping the same Plan B mount interface.

Does it work with Plan B suppressor mounts? Yes. The Sentinel is a Plan B device, so a Plan B suppressor mount fast-attaches over it and comes back off without disturbing the flash hider.

What thread pitch does it need? It threads onto a 1/2×28 muzzle, the common pitch on .223 and 5.56 AR-15 barrels.

Buy the Breek Arms Plan B Sentinel Caged Flash Hider, .223/5.56, 1/2×28

If your carbine spends time in a bag, a rack or a truck, a caged flash hider earns its keep the first time an open-prong device would have hooked a sling. Order the Sentinel with the rest of our class 3 parts and accessories from our Lubbock, Texas gun shop for fast, insured shipping.