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 round and 10mm round. After The Waters of Life, the 5.56 round becomes more common as enemies will use assault rifles more often than .32 hunting rifles. The 5.56mm rounds' world model is a black box magazine (resembling the magazines from the Chinese assault rifle).

Weapons using this ammunition

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

Locations
5.56 rounds are typically found in raider, Talon Company, and super mutant camps. Notable areas to search include Downtown DC and the Metro tunnels underneath the Downtown area. However, 5.56 rounds appear to be scarce early in the game. Large amounts of 5.56 rounds can be acquired quickly through several means:
 * At Fort Independence, Brotherhood Outcast Casdin will trade technology 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.
 * In the Fallout 3 add-on The Pitt, 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 type of ballistic firearm ammunition, including 5.56 rounds.