In the original arcade version, weapons like the M-16A1 Rifle or the Pistol have limited ammunition and disappear after the ammo runs out. In the popular hacked versions (often confused with the "20-Gun" label), the game mechanics are altered to provide:
Most firearms no longer deplete their magazines, allowing you to blast through waves of poachers and dinosaurs without reverting to punches. Cadillacs And Dinosaurs 20 Gun Rom Download
You can keep a machine gun through almost an entire stage if you’re careful. In the original arcade version, weapons like the