It looks neat, but performance is unimpressive.
328 FPS is only about a third of the muzzle velocity of 45 ACP pistol ammo. Rifle rounds can clock in at 10 times that.

For about $60 you can get a pellet pistol that shoots the same round @450fps.
I admit, it looks kinda cool, and I like to see kids doing this kinda stuff (as long as they don't hurt anything), but it's basically a reverse- engineered rail gun.
Still, kinda cool though.

I guess it can make a really nice nail gun.

@Jon A.
I'd like to see something that unlocked it's full potential in a prototype.

Pretty awesome if you ask me. This guy has basically built a prototype, man portable, rail gun. Assuming that he funds himself and doesn't have a well funded R&D lab, this is even more amazing when put into the context of the millions (if not more) spent by the U.S. government on R&D for a military use rail gun, which has come to nothing.

Not bad for the first try of a hand held rail gun. Here's what the Navy worked on. http://www.youtube.com/watch?v=4OqlTXwLG40

what is the weight of the projectile it is slow, but if it is 3 X heavier than a 45 ACP than it would deliver the same power to the target

Always be impressed with the effort required to make something new work even modestly well.
It suffers from the simple fact that we cannot store much electrical energy in any battery or capacitor with anything like the energy density of chemical or even compressed gas technology.
New advanced technology air guns easily outperform firearms and any conceivable portable rail gun using todays lithium air or other battery technology. That is in a package defined as portable by weighing less then 2 kilos and delivering useful energy out to 2 km into 2 cm.

It is indeed an impressive feat, even if it's an implementation of known technology and provides little in the way of a viable war machine in its current state. I doubt the specific requirement of delivering "useful energy out to 2 km into 2 cm" as core to usefulness. For most warfighters, delivering useful energy out to 200 m into 20 cm would be plenty, particularly if it did it quickly and (relatively) silently. Did anyone notice the distinct lack of noise produced by this? Try that with a chemical accelerant..

Note to all other commenters:
"Gauss Rifles" and "Rail guns" are two entirely different things. A gauss rifle uses sequential magnetic accelerators. A coil gun uses two (or more) electrified rails and the Lorentz force to accelerate a projectile.