|Type||Personal defence weapon|
|Place of origin||Czech Republic|
|Manufacturer||Czech Weapons (ČZW)|
|Parent case||.22 Hornet|
|Case type||Rimless, bottlenecked|
|Bullet diameter||4.28 mm (0.169 in)|
|Neck diameter||4.90 mm (0.193 in)|
|Shoulder diameter||6.88 mm (0.271 in)|
|Base diameter||7.56 mm (0.298 in)|
|Rim diameter||7.65 mm (0.301 in)|
|Rim thickness||1.24 mm (0.049 in)|
|Case length||30.10 mm (1.185 in)|
|Overall length||41.00 mm (1.614 in)|
|Maximum pressure||430 MPa (62,000 psi)CIP|
|Source(s): Small Arms Defense Journal|
It was designed and has been manufactured by ČZW for use in their ČZW-438.
The cartridge is based on a .22 Hornet cartridge converted to a rimless design and necked down to .17 calibre. The .17 Libra has been standardized by C.I.P. to a pressure of 4300 bar.
- .17 Libra [4.38×30mm]: A rimless varmint hunting and sport-shooting cartridge.
- .17 Rimmed Libra [4.38×30mmR]: A rimmed varmint-hunting and sport-shooting cartridge for use with break-open actions.
- .17 Libra Magnum [4.38×??mm]: A longer, more powerful rimless round for use in pistols or Personal Defense Weapons.