For a .223/5.56 flash hider, you need a wrench that’s 1 3/8″ or 35mm wide. You can use a monkey wrench, crescent wrench, or adjustable wrench for this size. Some flash hiders require a crush washer (specific to the threading of your barrel), which should be included with the purchase of the flash hider. If it’s not, you can usually find them at your local hardware store.
When installing the flash hider, make sure to apply some torque (3-6 ft-lbs) in a clockwise direction. Be careful not to over-tighten, as you could damage the threads on your barrel. If you’re unsure, it’s always best to take it to a gunsmith or qualified individual to have it installed.
Johnny Answered question July 5, 2022