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.