FAMAS, M416, M249, Mk 12 SPR, QBB-97, M4A1-S
5.56 millimeter, also known as 5.56mm (Green) in the game, is a type of ammunition currently used by six weapons. The power of 5.56mm is on par with 7.62mm (Blue) ammunition. but usually considered slightly better. All guns in surviv.io that use 5.56mm ammo are quite reliable and are typically used throughout a game.
Weapons using 5.56mm
3-round Burst fire. Similar to the UMP9, but with higher damage.
Fully automatic assault rifle, comparable to the AK-47 but with higher fire rate, better DPS, and lower accuracy.
Very rare weapon with extremely high fire rate and capacity. Considered one of, if not the, best gun.
Mk 12 SPR
Marksman rifle, comparable to the M39 EMR with greater fire rate.
Fairly rare LMG. Mostly found in airdrops. Similar to M249 with smaller capacity.
A silenced version of the M416, with better DPS as well. Very rare, only found in Golden Airdrops
The 5.56mm projectiles are green-colored.
The ammo is based off of the 5.56×45mm NATO cartridge, as all 5.56mm weapons in the game use that cartridge in real life.
The QBB-97 is an exception, as although the version in-game is an export variant that uses 5.56×45mm NATO, non-export versions uses its own 5.8×42mm ammo.
The 5.56mm casing is shown with a rim, even though the real-life cartridge is rimless.
This is the first new type of ammunition added to the game- originally, surviv.io only had 9mm, 7.62mm, and 12 gauge.