What's a carpenter with too much slack time do?
Those were framing hammers...just with the hatchet option. I've seen them used alot.ditto what the previous people said. He did an awesome job of tearing up that rafter above his head when he threw them up and they got stuck. I also noticed that it looked like he modified the hammers. Those don't look like any of the hammers I've ever seen. I know there are variants like shake hammers and the such, but it doesn't look like any of the "specialty" hammers either... It looks like a typical claw hammer with one of the sides of the claw cut off.