BB

 are a type of ammunition in Fallout, Fallout 2 and Fallout 3.

Fallout and Fallout 2
BBs are going to be a very useless ammo type to most characters. They're heavy, they're rare, and 2/3rds of the guns that chamber them are useless compared to the starting guns. However, if you run across Bob's Pre-owned Car Mart, or revive the frozen soldier in Sierra Army Depot, you might find the Red Ryder LE BB Gun, which makes BBs deadly little buggers.

Weapons using this ammunition

 * Red Ryder BB Gun
 * Red Ryder LE BB Gun
 * Jonny's BB Gun

Fallout 3
BBs are a small guns ammunition found in Fallout 3. They are used in only one weapon, the BB gun.

Locations

 * On top of VAPL-58 Power Station: a gun and 3 ammo containers.
 * NW from Scrapyard there is a power station. The first power pylon south of it has a gun and 2 ammo containers.
 * 300 rounds on the assembly line of Mothership Zeta Cargo Hold section.
 * Over 100 to the right on a shelf next to 2 BB guns just before you enter Haley's Hardware (Point Lookout)