sorry, I don't have a video of one of these, I built a prototype.. test fired it and it was great, Its just I have been out of co2's ever since.. I do plan on making another one.
Its really simple actually.. its an airsoft barrel, airsoft hopup unit, tire valve and co2 inflator.. in that order..
oh and of course the airsoft magazine...
The tire valve is from a bike tire.. I just cut off some of the excess rubber until it was a tight fit into the hopup...
The hopup design is quite simple.. it has an air inlet, a bb inlet, and a barrel outlet.
The air just goes through the air inlet.. and the BBs are pushed up by a spiring in the magazine.. the BBs are pushed into the air stream coming from the air inlet.. the air stream then pushes those BBs out the barrel.
Now my design utilizes an airsoft hopup that puts backspin on the BB causing it to fly further.
With this coming up again, I think I am finally going to build one of these the right way.. and expierenment by putting an expansion chamber between the co2 inflator and the hopup.