.22 CB Cap is a variety of .22 caliber rimfire ammunition

Ammunition

Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...

 which has a very small propellant

Propellant

A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

 charge (usually no gunpowder

Gunpowder

Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

, just the primer

Internal ballistics

Internal ballistics, a subfield of ballistics, is the study of a projectile's behavior from the time its propellant's igniter is initiated until it exits the gun barrel...

), 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

Internal ballistics

Internal ballistics, a subfield of ballistics, is the study of a projectile's behavior from the time its propellant's igniter is initiated until it exits the gun barrel...

).

The original .22 CB cartridge has the same case as the .22 BB

.22 BB

.22 BB Cap is a variety of .22 caliber rimfire ammunition. .22 BB cap and .22 CB refer to cartridges that are low velocity and project reduced noise. These rimfires closely resemble a .22 caliber air rifle in power and are often used for indoor shooting and close range pest control...

, but there are now low-power .22 rounds sold as .22 CB Short and .22 CB Long which come in the more common .22 rimfire cartridge cases. The longer cases will allow the rounds to be fired in magazine fed firearms, in which the tiny CB Cap cases would jam. So while having the same length, the modern .22 CB Short and the .22 Short are two different cartridges. The CB has a reduced powder load and is kept (as mentioned above) between 350 and 700 ft/s, while the Short with an increased powder amount launches the same 29gr bullet around and above 1000 ft/s.

Specifications

• Case length:
  • Cap: 0.284 in (7.2 mm)
  • Short: 0.423 in (10.7 mm)
  • Long: 0.595 in (15.1 mm)
• Bullet weight:
  • typically 20 to 29 grains
    Grain (measure)
    A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
    
    (1.30 to 1.88 g)