What's the most bullet-resistant material?

[Clump]

It's hard to explain how this works, but in short, i'm using the propulsion a bullet striking a wheel provides and using the new belt for power to the wheels and I need to know the best way to make a casing the bullets can't get through. In my experience the metal rods and barrels make good casings but I want to know if there's a better way.

[Mr_Rat37]

in the miscellaneuos section there is an item that is a bullet proof sheet

[no]

A couple bulletproof sheets

[Clump]

yeah i know about them, but they don't seem as effective as the others, i was just wondering

[Carl weezer]

Put it at a angle.