The BMD is a unique blast shield that allows the muzzle brake contained inside it to continue to function as normal with regard to muzzle climb mitigation. The patent pending design features unique 'through' ports that connect the muzzle brakes vertical vents to the outside atmosphere. This feature allows the brake to function while within the device unlike other system that alter the way the original device works and inevitably remove or massively reduce efficiency. The device also features sets of 'diffuser' grids positioned towards the top of the blast shield that assist in allowing gas to vent upwards as well as forwards at the time of firing assisting even further in muzzle control. Concussive muzzle blast is directed forwards down range and away from other shooters and team mates. Radial teeth at the exit aperture help to disrupt blast gas at it exits the device. - The BMD is mounted to the DGN556B Muzzle Brake through the use of an adapter collar. The collar is designed to fit as wide a range of brake outside diameters as possible and can effectively be mounted within the following size range: .855'' to .872'' Diameter. It is recommended that you use a quality set of vernier and check the outside diameter of your muzzle device before ordering. Diameters outside the ranges listed may need additional gunsmith work to be fitted or may not be used with this product. Measurements should be taken from the circular section of the brake marked with the 'LANTAC' logo. - The BMD mounts to the collar via the use of two rugged clips that must both be depressed together in order to remove the device from its mount.. - The device ships with a vial of Rocksett that must be used to ensure all mounting set screws are retained in place when the adapter is mounted to the brake. - SPECIFICATION: - Caliber: 5.56X45mm / .223 - Material: Milspec Gun Steel - Finish: Black Oxide - Dimensions: L: 2.570'' DIA of body at largest point: 1.600'' at smallest point: 1.185'' - Width at mounting clips: 1.785'' - Weight including all mounting hardware: 7.3oz - Designed for the DGN556B Dragon Muzzle Brake only - Full instructions included - Rocksett Included - Made in the USA.