DIY Piston Valve for Single or Multi Shot Nerf, Air-soft or Other.

Hey guys.
Sorry for a year or so gap between activity on this site... i have been a little occupied with school/work/gaming addiction. Now i feel it is time to publish something new.

As i have somehow destroyed my launcher yet again, i will be making a replacement. it will be a small caliber (in comparison to other "air cannons") and will hopefully be more accurate than my last one. In terms of power i don't hope to get much more than the ability to knock down a coke can at 10m well when i say i don't hope, i mean i don't want anything more powerful. 

so anyways, here is a bit of a sneak peak of some of the internals of my next launcher. 

...also anyone got any ideas of what this thing should look like when I'm done?   

Here is a video of it cycling. 
http://www.youtube.com/watch?v=QeJtJ-AveJE&feature=player_embedded