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|.22 Flobert CB|
A .22 CB cap, .22 short, and .22 Long Rifle
|Place of origin||France|
|Parent case||.22 BB|
|Bullet diameter||.222 in (5.6 mm)|
|Neck diameter||.225 in (5.7 mm)|
|Base diameter||.225 in (5.7 mm)|
|Rim diameter||.271 in (6.9 mm)|
|Rim thickness||.040 in (1.0 mm)|
|Case length||.420 in (10.7 mm)|
|Overall length||.520 in (13.2 mm)|
|Source(s): Cartridges of the World, 11th Edition|
.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.
Designed to be a cross between the .22 BB and .22 Short, and first catalogued in around 1888 (though probably first made before that), it "managed to combine about all the disadvantages...[of both] into one generally useless cartridge", being no more accurate than either, while being noisier than the .22 BB Cap and requiring a backstop as strong as the .22 Short, negating the BB Cap's advantages for shooting indoors.
Recognizing its general uselessness, many American ammunition manufacturers dropped it around 1942, while RWS in Germany, Eley-Kinoch in Britain, and Alcan continued to offer it into the 1970s. In some European countries, 6mm Flobert cartridges are still manufactured and sold, as they are used in "flobert revolvers" which are usually unaffected by gun laws (e.g. in Czech Republic, Slovakia and Hungaria, flobert revolvers fall within the same weapon category as air rifles).
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). The original .22 CB cartridge has the same case as the .22 BB, 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 29 gr bullet around and above 1000 ft/s.
- 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 18 grains (1.15 g)
- Cartridges of the World 11th Edition, Book by Frank C. Barnes, Edited by Stan Skinner, Gun Digest Books, 2006, ISBN 0-89689-297-2 pp. 490, 492
- Cartridges of the World 11th Edition, Book by Frank C. Barnes, Edited by Stan Skinner, Gun Digest Books, 2006, ISBN 0-89689-297-2 p. 476
- Barnes, p.273, ".22 CB Cap".
- Barnes, Frank C., ed. by John T. Amber. ".22 CB Cap", in Cartridges of the World, pp. 273, 282, & 283. Northfield, IL: DBI Books, 1972. ISBN 0-695-80326-3.