Comstock Armory Full Size Plan-B Flash Hider, 5/8x24, 9mm, Black Nitride

Comstock Armory Full Size Plan-B Flash Hider, 5/8x24, 9mm, Black Nitride

The Comstock Armory FHL-58-9 is a full-size flash hider with 5/8x24 barrel threads and a Plan-B-compatible suppressor-mount interface. It pairs flash reduction with a gas-directing design intended to reduce wear on a suppressor's blast baffle. This specialized muzzle device is an option for buyers who want a flash hider that also serves as the mounting point for a compatible suppressor system.

High-strength 17-4 PH stainless steel and a black nitride finish define this configuration. The bore accommodates bullets up to 9mm, including .350 Legend, while the 5/8x24 thread pattern identifies the barrel connection. Caliber clearance and thread compatibility are separate requirements; both must match the intended firearm.

Choose the full-size flash hider for your 5/8x24 setup. Shop the Comstock Armory FHL-58-9 at BattleHawk Armory.

Flash Reduction with Blast-Baffle Protection

The FHL directs expanding gas outward rather than relying on an open passage alone. That geometry provides flash-hider function while helping reduce the gas exposure that contributes to blast-baffle wear. It gives this device a role both with and without a compatible suppressor, without presenting it as a dedicated recoil brake.

Full-Size Steel Construction

A 2.00-inch overall length and 1.8-ounce weight keep the device's physical specifications clear when comparing muzzle accessories. It adds approximately 1.36 inches beyond the muzzle; overall device length is not the same as added length. The rotationally symmetric layout does not require timing to a particular clock position.

Plan-B Compatibility and Purchase Considerations

The suppressor-side connection works with compatible .900-24 adapters, including Comstock LPA, Q Plan-B and Rearden Atlas. Matching the interface alone does not establish complete system compatibility. Confirm the suppressor's caliber rating, internal clearance and aftermarket-mount warranty terms before purchase. This product is the muzzle device, not the suppressor or suppressor-side adapter.

Product Specifications

• Manufacturer: Comstock Armory
• Model / SKU: FHL-58-9
• UPC: 850069580162
• Product type: Full Size Flash Hider
• Barrel threads: 5/8x24
• Bore capability: Up to 9mm; includes .350 Legend
• Suppressor interface: Plan-B-compatible .900-24
• Compatible adapter families: Comstock LPA, Q Plan-B, Rearden Atlas; complete-system fitment required
• Material: 17-4 PH stainless steel
• Finish: Black nitride
• Overall length: 2.00 inches
• Approximate length added beyond muzzle: 1.36 inches
• Weight: 1.8 ounces
• Wrench flats: 13/16 inch
• Timing: Not required; rotationally symmetric

Included Item

One Comstock Armory FHL-58-9 muzzle device.

Frequently Asked Questions

Does the FHL-58-9 require timing?

No. Its rotationally symmetric design does not require timing with shims.

Is the FHL-58-9 compatible with .350 Legend?

The muzzle-device bore supports bullets up to 9mm, including .350 Legend. The barrel still needs matching 5/8x24 threads, and any suppressor must be appropriate for the cartridge and configuration.

What should I know about a 14.5-inch pin-and-weld application?

The Comstock 5/8 spacer ring is required for that application. Have a qualified gunsmith confirm the complete configuration and final dimensions; the device's stated overall length is not a guarantee of finished barrel length.

Order the Comstock Armory FHL-58-9 from BattleHawk Armory for a full-size flash hider with a defined Plan-B interface and black nitride steel construction.

Explore Comstock Armory accessories at BattleHawk Armory.

Shop the Comstock Armory FHL-58-9 at BattleHawk Armory.