What you will need:
1 Lever
2 Redstone
4 Redstone Torches
4 Dispensers
4 blocks of your choice (Preferably not flammable)
36 stacks of Fire Charges

Method:
1. Craft/mine/collect the required matrials
2. Make this minigun, but DON'T USE ARROWS (a: Arrows don't burn b: Arrows aren't on the list)
3. Put the 36 stacks of Fire Charges in the dispensers.
4. FIRE AT WILL!

Useful for fighting noobs in wool/wood/[insert flammable block here] spaceships/fortresses/[Insert your enemy's type of base here]!
Good luck!