The ČZW 438 was a Czech submachine gun designed and manufactured by Czech Weapons s.r.o in prototype form only in 2004.
The developmental history of the ČZW 438 is not well documented, however it is said to be designed with a "high powered caliber for massive stopping power". It, like most other ČZW weapons, appears to be a testbed for delayed blowback technology.
The weapon is also known as the PDW .17 Libra in certain publications.
The ČZW 438 is a submachine gun using lever delayed blowback. The weapon features a folding stock; the weapon uses an experimental cartridge not known to be used by any other weapon, the 4.38×30mm Libra cartridge, hence its designation.
- ČZW 438 9M
Version of the ČZW 438 chambered for 9×19mm Parabellum as opposed to 4.38×30mm Libra, a slower rate of fire and a M4-style telescoping stock. The weapon can theoretically be converted back into 4.38×30mm Libra as hinted by the weapon's description, stating that it "proves the system's modularity".