.300 Blackout 30-Round Mags

is an FSS attachment featured in Call of Duty: Modern Warfare. It is available as a conversion kit for the M13 assault rifle.
Compared to the standard M13 magazine, it does not change the ammo count. However, it increases the damage range of the projectiles, as well as removing visible tracers and enemy skulls from the map. As a downside, the bullet velocity and recoil control are reduced.
Category:Call of Duty: Modern Warfare (2019) Attachments