.22 CB Cap (Conical Ball Cap, known as a 6mm Flobert in Europe) is a variety of .22 caliber rimfire ammunition which has a very small propellant charge (usually no gunpowder, just the primer), resulting in a low muzzle velocity of between 350 and 700 ft/s (110 to 210 m/s). This is similar to the muzzle velocity produced by a low to mid-power .22 pellet gun, however the bullet from a .22 CB cartridge is significantly heavier than a typical airgun pellet and therefore carries more energy. Due to their low power, CB rounds can be trapped by most pellet gun traps. In longer rifle barrels the CB has a very quiet, seemingly non-existent report due to the lack of residual pressure at the muzzle (see Internal ballistics).