.300 AAC Blackout (New Brass) - Manufactured by Jamison Brass & Ammo
The 300 Blackout was developed by Advanced Armament Corporation in hopes to be a direct competitor or possibly even replace the current military standard 5.56x45mm NATO cartridge. The 300 Blackout is based off the 30-221 Fireball, but has a shorter case length and so that it feeds easily in a rifle chamber and in STANAG magazines. The 300 Blackout was developed specifically around the AR platform and was SAAMI approved in early 2011. Since then the 300 Blackout has grown exponentially in popularity.