Griffin Armament Gate-LOK Flash Comp XHP556FC (also known as the Griffin Armament M4SD 5.56 Flash Comp or GATE-LOK™ FlashComp 5.56mm).
This is a multi-function muzzle device that intelligently combines the roles of a muzzle brake, tactical compensator, and flash suppressor in one compact package. Designed specifically for the GATE-LOK™ quick-detach suppressor mounting system, it serves as a direct-thread mount for Griffin’s M4SD-series suppressors (M4SDK, M4SD2, 30SD, 30SDK) while also working with the QD Blast Shield. It includes a sacrificial baffle that helps extend suppressor service life by absorbing initial blast and heat.
Key Features & Specs
- Performance: Excellent flash hiding with 3-prong-style tines, strong recoil mitigation, and reduced muzzle rise for faster follow-up shots. It balances gas redirection for control without excessive side blast or concussion.
- Material & Finish: CNC machined from heat-treated 17-4 PH stainless steel with a durable black nitride (Melanite QPQ or similar) finish for corrosion resistance and longevity.
- Dimensions:
- Overall Length (OAL): 2.21 inches (some listings note ~2.25" for pinning/welding considerations).
- Diameter: 0.863 inches.
- Weight: Approximately 2.65–2.9 oz.
- Threading: 1/2x28 TPI (standard for 5.56/.223 AR-15 barrels).
- Mounting: GATE-LOK™ interface for fast, repeatable suppressor attachment with minimal POI shift. Includes a shim kit and over-travel stop washer for proper timing and secure installation.
- Additional: Pre-drilled for easy pinning and welding (ideal for 14.5" barrels to reach 16" overall legal length). Achieved a perfect 5/5 score and NTOA Gold Seal of Approval in National Tactical Officers Association testing.
- Bore: ~0.251 inches.
The Flash Comp is praised for its hybrid performance — it delivers noticeable recoil reduction and muzzle control like a dedicated compensator while maintaining strong flash suppression, all in a low-profile design that doesn’t add excessive length or weight. Users report it performs well on 14.5"–16"+ barrels, with clean gas venting and no excessive “pinging” or ringing.
Who It's For
- AR-15 builders running Griffin GATE-LOK suppressors who want a single muzzle device that handles flash hiding, recoil control, and suppressor mounting.
- Tactical, duty, or competition shooters needing balanced performance without swapping devices.
- Users who prefer a nitride-finished, stainless steel device with proven real-world testing (NTOA approved).
- Those building pinned/welded SBR/legal-length configurations.
Compatibility Note: Optimized for .223/5.56 NATO with 1/2x28 threading. Not for direct use with non-GATE-LOK suppressors (though it can function standalone as a muzzle device).
