|Ammo Type||5mm Round|
The Minigun is a Big Guns weapon in Fallout 3. The Minigun uses 5mm Rounds which are pretty common in the Capital Wasteland, however it can use up 240 rounds in a matter of seconds, only the Gatling Laser beats the Minigun in terms of quick fire.
It's the most common big gun in the game and can often be found on Super Mutant Brutes. You can usually find around 3 or 4 Minguns just within The Mall. They can also be found on Brotherhood of Steel, Outcasts and Enclave soldiers.