watch it in slow motion: http://www.youtube.com/watch?v=9sB6HnmbswI
video of how to build it: http://www.youtube.com/watch?v=FvfOdmhf2Fw
PVC slug into TV: http://www.youtube.com/watch?v=oPdLBt5x2DY
more carnage: http://www.youtube.com/watch?v=Fhz_ScFrtUY
My spud gun finally penetrated metal. Bullet was very simple. The barrel of the gun is 2" PVC, so I bought 1.5" PVC and built it up with duct tape to make it fit the 2" barrel fairly tight. I filled the center with crumbled up newspaper (you will see me pulling paper out of the hole the bullet makes in my car). The 'casing' of the bullet (the 1.5" PVC) was intact after the hits. Pretty cool that it could bust a hole in the metal like that.