Icon disambig
For the Fallout, Fallout 2 and Fallout: New Vegas ammunition round, see .223 round.
Icon info
This is an overview article which contains background information and cross-game comparisons. For game-specific information and stats, see the articles linked on the right.
Gameplay articles
Fallout 35.56mm round
Fallout: New Vegas5.56mm round
5.56mm, armor piercing
5.56mm, hollow point
5.56mm, surplus
5.56mm, match
Fallout 45.56mm round
Fallout 765.56 round
Fallout Tactics5.56mm

The 5.56mm round is a type of ammunition in Fallout 3, Fallout: New Vegas, Fallout 4, Fallout 76, and Fallout Tactics. All weapons using 5.56mm rounds can use .223 rounds.


The 5.56x45mm round is a rifle cartridge derived from the .223 Remington, originally developed for the M16 service rifle of the United States Army.[1][2] It is a rimless, bottleneck cartridge that offers tremendous wounding potential under the right condition. Its performance and popularity among military forces endures despite the Great War: By 2287, it has served Americans for over two centuries, from the United States Army to the New California Republic Army.


5.56mm roundEdit

FoT 556mm ammo
Ammunition. Caliber: 5.56mm.
In-game description, Fallout Tactics: Brotherhood of Steel

Ammunition. 5.56mm caliber. The 5.56mm round is a standard intermediate caliber rifle cartridge used in most military, hunting and sporting rifles with almost the same external dimensions as the .223 round, but while the external case dimensions are very similar, the 5.56mm and .223 differ in both maximum pressure and chamber shape.

5.56mm, armor piercingEdit

5 56mm Round
Gameplay article: Fallout: New Vegas

Ammunition. 5.56mm caliber, armor piercing. Armor piercing rounds are designed for punching through armor plating, for this purpose they have a greatly strengthened case with a specially hardened and shaped nose. Due to the high muzzle velocity and penetrative properties of the round, damage to the target is slightly reduced.

5.56mm, hollow pointEdit

5 56mm Round
Gameplay article: Fallout: New Vegas

Ammunition. 5.56mm caliber, hollow point. Hollow point bullets mushroom and break up on impact, causing massive trauma on fleshy, un-armored targets. However, this also means they break up when they hit things like armor plate, drastically reducing the weapon's penetrating power.

5.56mm, surplusEdit

5 56mm Round
Gameplay article: Fallout: New Vegas

Ammunition. 5.56mm caliber, surplus. Surplus ammunition is poor grade ammunition made in larger quantities by using corrosive materials in their construction. The resulting process is a slightly more damaging round but at the cost of more regular maintenance on a firearm due to the highly damaging corrosive materials used in the round's construction.

5.56mm, matchEdit

5 56mm Round
Gameplay article: Fallout: New Vegas

New ammunition added with the add-on, Gun Runners' Arsenal. Match ammunition is precision-made so that every bullet has the same powder, shape, and weight. Match ammunition is often used in tournaments, sight alignment, and sniping. This ammunition type gives a slight damage boost and a significant reduction in the weapons spread.

Behind the scenesEdit

The real-life equivalent is the 5.56x45mm NATO intermediate rifle cartridge, fired by most assault rifles and light machine guns used by NATO countries. The .223 Remington is the 5.56's parent cartridge.


  1. Vault Dweller's Survival Guide p.5-17: "Rifle caliber ammunition. The FMJ stands for Full-Metal Jacket, which describes the bullet that is used in the round of ammo. A FMJ bullet is very tough, and has pretty good penetration without sacrificing good expansion. In other words, it‘s an average round."
  2. Fallout Official Survival Guide p.119: ".223 Full Metal Jacket (FMJ): This is the same ammo used in the late 20th century by various military rifles, including the M-16. A good, basic, hard-hitting round."
Community content is available under CC-BY-SA unless otherwise noted.

Fandom may earn an affiliate commission on sales made from links on this page.

Stream the best stories.

Fandom may earn an affiliate commission on sales made from links on this page.

Get Disney+