Nerf Vortex dart cannon ,help

[django]

Gday chaps, I recently seen this video on you tube,anyone here?
and want to make one of these babys .Ive just found that I can get those Nerf Vortex Howlers( small ones) for $2.50 Aust each and after seeing this video I want to make one.

I dont know what sort of valve the guy's using?,how the Barrel seals, chamber size etc if anyone can offer assistance I thank you!?.I can use my 20 co2 bottle and reg but will have to make some sort of adaptor so the co2 line fits the gun,I dont think he uses a Qev it doesnt sound like one?...

[psycix]

Its hard to see what he is using, but you could accomplish the same thing by using the following:
-Bolt action barrel (duh)
-Piston or diaphragm valve (homemade or sprinklers/QEVs)
-Slide valve as pilot
-Regulator from tank hooked up to slide valve
-Safety popoff!