That GAU-8/A Avenger Gatling Gun is great for bad days.
Each round is 30mm, and just six shots is enough to destroy modern Russian armor. Each round is 11.4" and weighs 1.53+ pounds. The API (Armor-Piercing Inceindary) projectile incorporates a depleted-uranium penetrator. The Avenger's maximum rate of fire is 4,200 rounds per minute.
Here's a little comparison of how big that whole gun is. See it? It about the same size as that Volkswagen Beetle.