Aluminum 3 Port “Bruin” Muzzle Brake Aluminum 3 Port “Bruin” Self-Timing Muzzle Brake Specifications: Thread Pitch: 5/8-24 Length: 2.230 inches long Weight:1.2 ounces Material: Aluminum, Hard coat anodized black. Diameter: .995 with a taper on timing nut to .970. Bore Diameter: Intended for cartridges as small as 223 Remington all the way up to 338-378 Weatherby! Each and every muzzle brake is carefully inspected, chamfered, deburred & polished before shipping. J&A Outdoors – Firearm Solutions – Shooting Products (jaoutdoors.com)