The Mossberg 500 is a family of American-made pump-action shotguns chambered in 12 gauge.
Introduced in 1961, all Mossberg 500s are based on the same design, although there are a multitude of different models available, with varying barrel length, magazine capacity, sights, bore size, choke options, finishes and "furniture" (stocks, grips etc.). Perhaps the most notable variant of the 500 is the Bullpup model, which houses the shotgun in a distinctive bullpup stock. A unique item offered by Mossberg for the Model 500 is a line launcher kit, which uses a special blank cartridge to propel a shaft with an optional floating head and a light rope attached to it; a canister hung below the barrel holds the line spool.
The Mossberg 500 is notably used by the United States military.
In Predator, Billy has a Mossberg 500 with the stock removed underslung on his M16 assault rifle. While never shown prominently firing the shotgun in the film, there is a brief instance where he appears to run out of ammo for his rifle, and fires off a single shot before the film cuts to the next scene; it is often overlooked as he is in the distant background in this scene and there is no sound effect for his shotgun firing.