An Uzi with a silencer, much like the one used in the The Indwelling
The Uzi is an Israeli sub-machinegun that is used by the forces of both the Global Community and the Tribulation Force. It's first seen in The Indwelling: The Beast Takes Possession as GC forces surround the stage where Nicolae Carpathia is assassinated. One GC guard uses it to kill Jacov by whacking him with the gun's butt. It was also used by Tsion Ben-Judah when he helped the Jews defend Jerusalem against the assault of the Global Community's Unity Army.
In The Indwelling An Experience in Sound and Drama
In the audio movie version of The Indwelling, Jacov is shouting, "Dr. Rozensweig needs me!" After the guard tries to get him to stay back from the stage, Jacov cries, "You don't understand! He needs my help!" Jacov is then whacked with the butt of the Uzi, causing him to fall down the stairs and break his neck.