Brass is available from Midway (800-243-3220)
As long as the chambers are squeeky clean and perfectly dry the Jet is fun, but it's pretty common to run into a situation where the bottleneck case sets back just a tad in the chamber and ends up binding the cylinder rotation.
I see ammo at gun shows, but it hasn't been loaded in some time. It might be worth buying a box just for grins, but back when I had one I just got S&W to fit a .22lr cylinder to it.