DEB-M21
The M21 functions based on the well-tested blowback method of operation and uses a number of parts from the Uzi, including the magazine. The M21 can be fired fully automatic only and there is no provision for semi-automatic fire. The cyclic rate of fire can be adjusted by adding or removing rubber washers behind the bolt. The minimum is 690 rounds per minute while the maximum is 895. There is also no safety, aside from the inability to fire the weapon when it is folded. There are no iron sights, but as mentioned above, an optical sight can be easily attached. One final point worth mentioning is the charging handle. It is found underneath the muzzle and is pulled rearward to chamber a round. Its location also allows it to serve as a handstop, preventing the firer's hand from slipping in front of the barrel during firing.
Picture from Giovanni Tendas