Thanks for pointing that out to me.
Looks like Tippmann has released a propane expansion (not combustion) powered pball gun. I think the cylinder under the hopper with the heat sinks is an expansion cylinder.
I'm not sure about their claim that propane is not temperature sensitive. It also has a variable equilibrium pressure set by temperature. I suspect that Tippmann may include an internal regulator to deal with some of this though. They don't need a high flow reg. Just one which can keep the expansion chamber at a consistant pressure just before each shot.
Want nearly free GBB gas?