Jengo
The Jengo Warden (No Top) is the armed version of the FND's roofless jeep, with a machine gun on the back. It is one of the easiest armed vehicles to steal early on.
Fights on the move. A companion can man the gun while you drive, which turns a patrol ambush into a running fight.
Kill the patrol riding it and take the jeep. Drive it to any vehicle pickup point to add it to your list. After that you can spawn it at pickup points instead of hunting for another one.
It is open-topped, so the gunner is exposed. The game's own joke is that one good flip and you are out of it.