5mm round

The  is an ammunition type found in Fallout, Fallout 2, Fallout 3, Fallout: New Vegas and Van Buren. It is used by various weapons, such as the Minigun.

Fallout and Fallout 2
In Fallout and Fallout 2, there are two types of 5mm ammunition, 5mm AP and 5mm JHP. 5mm was the standard US military round for bases located around the Core Region by 2077.

Van Buren
5mm rounds are still in use by NCR in 2253, and were used in all of NCR's standard-issue assault rifles. All of the NCR goons in Hoover Dam and Ballistic Orbital Missile Base 001 carry a bunch of spare magazines.

Used in

 * Assault Rifle