The following guns were used in the film The Jerk:
The Madman (M. Emmet Walsh) is seen using an M16A1 with a scope and a suppressor to try and take out Navin R. Johnson (Steve Martin). This scene is also briefly glimpsed on a TV set in the film Black Hawk Down.
The Madman is also seen carrying two MAC-10's in his arsenal.
Colt Python Revolver
The Madman also is seen pulling a Colt Python revolver when he chases Navin.