5.56mm Round (Fallout 3)

The 5.56mm round is a type of ammunition in Fallout 3.

Characteristics
Relatively speaking, the 5.56mm round is the third most common small guns ammunition found in the game, compared to the .32 caliber and 10mm rounds. After The Waters of Life quest, the 5.56mm cartridge becomes more common as enemies will use assault rifles more often than hunting rifles chambered in .32. The 5.56mm ammo's world model is a black curved box magazine (resembling ones utilized by the Chinese assault rifle).

Weapons using this ammunition

 * R91 assault rifle
 * Chinese assault rifle
 * Xuanlong assault rifle
 * Infiltrator
 * Perforator

Locations
5.56mm rounds are typically found on raiders, the Talon Company mercs, and at super mutant camps. Notable areas to search include the ruins of Washington, D.C. and the Metro tunnels underneath the Downtown area. However, 5.56mm rounds appear to be scarce early in the game, but large amounts of this ammunition can be acquired quickly through several means:
 * At Fort Independence, Brotherhood Outcast Casdin will trade technological items for 5.56 rounds, stimpaks, frag grenades, or RadAway. It is notable that Casdin's subtitles incorrectly say " .556 ammunition" instead of "5.56 ammunition". See the unmarked quest The Outcast Collection Agent.
 * 14 magazines spread throughout Metro Central, of which four near a female Talon Company merc behind a wrecked train in the waiting area.
 * Four ammunition boxes in the Arlington Public Library lobby, just to the left when entering.
 * Three boxes in the Super-Duper Mart, next to the Protectron terminal in the storage room.
 * Completing the quest Free Labor will unlock the ammo press. Located in The Mill of The Pitt, the ammo press converts any ballistics-based firearm ammunition or scrap metal into any other types of ballistic firearm ammunition, including 5.56mm.