The Area 419 Hellfire Self Timing Muzzle Brake 223/6mm Black Nitride 1/2-28 from Area 419 Firearms LLC delivers exceptional recoil reduction and precision timing for calibers up to .243 (6mm) such as 223, 5.56 NATO, 204, and 17 cal. This self-timing brake installs easily and will not turn as you torque the collar to lock, eliminating guesswork about port alignment, while a simple round knurled nut requires no tools to time the brake. Return to zero is excellent, so removing and re-installing the brake wont alter your zero. To install, torque the universal adapter onto your barrel with a 5/8" wrench, then follow the left-hand-threaded brake/collar assembly onto the adapter until snug, rotate the brake level, push into the adapter to lock onto the taper, and tighten the collar by hand. The Hellfire combines rearward-facing ports for maximum recoil reduction, independently tested to outperform many brakes on the market with about 52% recoil reduction on a test rifle in 6.5 Creedmoor, and its proprietary port design controls muzzle rise without top porting. The face is engraved with caliber for correct orientation, and a horizontal line aids leveling. Crafted from heat-treated 17-4PH stainless steel, offered in Black Nitride or raw stainless (universal adapters in black), and manufactured on CNC machines in NW Ohio, it measures 1" OD brake and 1.1" OD collar, with the brake assembly extending roughly 2.6" from the thread shoulder.