The Uzi Israeli submachine gun is a self-repeating weapon (for single and continuous fire) operating on the principle of using the energy of a free lock with a primer puncture when the lock is in the final stage of forwarding movement. This solution allows you to use the so-called ejection of the lock, consisting in the fact that in the final phase of the return the lock does not hit the rear chamfer of the barrel, but is braked by the shell sliding out of the cartridge chamber, and then, under the influence of further pressure increase – thrown back into the rear position. The use of such a solution allowed the barrel to be extended to 260 mm while maintaining the conditions of reliable operation and safety of use. Whereas the barrel elongation increased the initial velocity of the projectile to 400 m / s. Shooting takes place from an open lock. By using a slide that covers and covers the barrel, the length of the weapon has been shortened and the wearer has been protected against the effects of breaking the shell with premature or delayed ignition. The lever for tensioning the lock moves in the cutout of the barrel chamber cover in its upper part. The lock is equipped with a fixed, protruding needle, supported by a return spring, which fulfills the function of a shock spring.