5.56mm round

The 5.56mm round is a type of small guns ammunition found in Fallout 3, Fallout: New Vegas and Fallout Tactics, named after the size of the bullet's diameter.

Fallout 3
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 hunting rifles. The 5.56mm rounds' world model is a black banana magazine (resembling the magazines from the Chinese assault rifle).

Obtaining 5.56 rounds
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, grenades, and Rad Away. It is notable that Casdin's subtitles incorrectly say ".556 ammo" instead of "5.56 ammo".


 * Uncle Roe at Canterbury Commons will allow players to invest in caravan merchants, such as Lucky Harith, and Crow. By investing, the merchants will begin to sell poor quality (and thus, cheap) power armor and energy weapons, which can then be traded to Brotherhood Outcast Casdin at Fort Independence. This can be repeated every 48 (in-game) hours. Chief Gustavo of Tenpenny Tower also carries cheap laser rifles and laser pistols that can be traded to Brotherhood Outcast Casdin.


 * In the Fallout 3 add-on The Pitt, completing the quest Free Labor will unlock the 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 ammo, including 5.56 rounds.

Weapons using this ammunition

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

Weapons using this ammunition

 * Light machine gun
 * That gun
 * Varmint rifle

Casing
5.56mm casing is used to create 5.56mm rounds at a workbench.

Weapons using this ammunition

 * M16A1
 * Ruger AC556F
 * XL70E3 Enfield
 * Steyr
 * Avenger minigun