CZ Model 25 Country Czechoslovakia Type Submachine gun Introduction 1948 Specifications Weight 3.27 kg empty (folding stock models Sa.25, Sa.26); 3.5 kg empty (fixed wood stock models Sa.23, Sa.24) Length 445 mm folding stock model folded (Sa.25, Sa.26); 686 mm fixed stock and unfolded folding stock Barrel length 284 mm Cartridge 7.62 x 25 mm 9 x 19 mm Rate of fire 650 rpm Feed system 24 or 40 round (9 mm Sa.23, Sa.25); 32 round (7.62 mm Sa.24, Sa.26)

The CZ Model 25 (formally, Sa.25 or Sa-48b or samopal vz.48b) was perhaps the best known of a series of Czechoslovak designed submachine guns introduced in 1948. There were four generally very similar submachine guns in this series: the Sa.23, Sa.24, Sa.25, and Sa.26. The primary designer was Vaclav Holek.

The Sa.23 series utilize a straightforwards blowback action, with no locked breech, and fire from the open bolt position. They also use a progressive trigger for selecting between semi-automatic fire and fully automatic fire. Lightly pulling on the trigger will fire a single shot. Pulling the trigger further to the rear in a continuous motion will fire fully automatically, until the trigger is released or the magazine is empty.

The Sa.23 series were the first production-model submachine guns with a telescoping bolt, in which the forwards part of the moving bolt extends forwards past the back end of the barrel, wrapping around that barrel. This feature reduces the required length of the submachine gun significantly and allows for better balance and handling. Handling was further improved by using a single vertical handgrip housing the ammunition magazine and trigger mechanism, roughly centered along the gun\'s length. The gun\'s receiver was machined from a single circular steel tube.

The design of the Sa.23 series submachine guns is most notable in the west for having heavily inspired the slightly later Uzi submachine gun.