There is no place to receive Explosive 5.56 Rifle Ammo aside from crafting or airdrops.
The blueprint can be made by random chance when researching a Blueprint Book.
Two explosive bullets can be crafted with the following ingredients:
It takes 10 seconds to craft the two bullets, for a full stack of 100 ammunition, it would take 8 minutes and 20 seconds.
Damage and Properties Edit
May 5, 2016 - Devblog 109 - All 5.56 Ammo now stacks up to 100 instead of 64.