How to get Acceltra Prime Barrel in Warframe?

Acceltra Prime Barrel is an item dropped from Void relics.
You can find the list of relics below, and click on the links to see how to get them.

Relics dropping Acceltra Prime Barrel

Other items:
Acceltra Blueprint - Acceltra Prime Blueprint - Acceltra Prime Receiver
Acceltra Prime Stock