Comstock Armory 5/8×24 Flash Hider

Comstock Armory 5/8×24 Flash Hider

The Comstock Armory 5/8×24 flash hider is the muzzle device you install when you need a compact, functional interface point between your suppressor system and your barrel — whether the can is on or off.

Built for 5/8-24 threaded barrels chambered in anything up to 9mm (including 7.62/.30 and 350 Legend), the FHC-58-9 is machined from 17-4 PH stainless steel and finished in black nitride, giving it the hardness and corrosion resistance to hold up through sustained fire. At 1.6 inches overall and just 1.5 ounces, it adds minimal length and weight to the host. Unlike most flash hiders, the FHC vents expanding gases outward rather than rearward — which means less blast baffle erosion over the life of your suppressor. Because the design is rotationally symmetric, it requires no timing or shims; install it, torque it, and move on.

Key Features — Comstock Armory 5/8×24 Flash Hider

• Compatible with .900″-24 adapters: Comstock LPA, Q Plan-B, and Rearden Atlas
• 17-4 PH stainless steel construction
• Black nitride finish
• 5/8-24 thread pitch
• Rated for bullets up to 9mm, including 7.62/.30 and 350 Legend
• 1.6″ overall length; adds 0.97″ to the muzzle
• 1.5 oz weight
• Rotationally symmetric — no timing or shims required
• 13/16″ wrench flats for installation and removal
• Effective flash suppression

Why This Product Stands Out

If you’re running a Q Plan-B, Rearden Atlas, or Comstock LPA suppressor system, the 5/8×24 flash hider solves the problem of what to keep on the muzzle when the can is off. Because it actually suppresses flash rather than just providing a mount point, you get real utility in both configurations. That’s the distinction most budget adapters miss entirely.

Furthermore, the gas redirection design protects your blast baffle by channeling propellant gases away from the first baffle face. Over thousands of rounds, that translates to a measurable difference in suppressor longevity — and for a shooter who takes can maintenance seriously, that matters. Beyond that, the symmetric geometry means no external adjustments, no shim packs, and no timing marks to align. Installation is the same every time.

Additionally, Comstock machines the FHC from 17-4 PH stainless specifically because the alloy balances high tensile strength with corrosion resistance better than standard carbon steel at this price point. The black nitride finish layers on top of that for added hardness and a consistent matte profile.

Ideal Use Cases

The following applications are a natural fit for this muzzle device:

• SBR or pistol-caliber carbine builds with Plan-B or Rearden suppressor systems
• Dedicated suppressor hosts where blast baffle wear is a long-term concern
• Duty or training builds requiring a functional muzzle device on the bare host
• 7.62/.308 and 300 BLK platform builds with 5/8-24 threading
• PCCs chambered in 9mm or 350 Legend needing a suppressor-ready muzzle device

Technical Specifications

Compatibility Information

Suppressor Mount Compatibility The 5/8×24 flash hider accepts any suppressor or adapter using the .900″-24 mount standard — specifically the Q Plan-B, Rearden Atlas, and Comstock LPA systems. Because these three adapters cover the majority of the modern suppressor market, compatibility is broad. Note that some suppressor manufacturers do not warranty their products when used with aftermarket mounts or muzzle devices — verify with your suppressor manufacturer before use. Additionally, always confirm bullet stabilization and use an alignment rod before running a suppressor on this device.

Host Caliber Compatibility Comstock rates this device for use with bullets up to 9mm diameter. That means it is suitable for 9mm PCC builds, 7.62/.30 calibers, .300 Blackout, and 350 Legend on 5/8-24 threaded barrels. It is not rated for use above 9mm/.30 caliber.

Manufacturer: Comstock Armory | Model: FHC-58-9 | Type: Compact Flash Hider / Suppressor Mount | Caliber: Up to 9mm / 7.62 | UPC: 850069580070 | SKU: FHC-58-9