Simplify the following text for a Grade 7 native English-speaking person.
Original: An Uzi is a type of submachine gun . There are many different kinds of Uzis : Mini Uzi , which is a smaller version of the Uzi , Micro Uzi ; which is only slightly larger than a standard pistol , Para Micro Uzi ; which was made for counter terrorist units , and the Uzi Pistol ; which is semi-automatic ( meaning it fires 1 bullet every time you pull the trigger ) .
Simplified: In general , the Uzi was a reliable weapon in military service .