picture two parallel rails made out of, say, 1/8" wooden dowel. the ammunition would be ball bearings maybe 2cm in diameter. they rails as i will call them would be about 1.7 cm apart, and would form a track that the ball followed and could not easily leave.
one of these rails would be conductive (wrapped in aluminum foil, perhaps), and connected to say, ground (it would work with vdd as well, just need different mosfets. but ill get to that).
the other rail would have small, evenly spaced conductive spots that were maybe 1.5cm in run and .5cm apart.
so youd need to make U shaped electromagnets, that had maybe a 2.3cm inner diameter, so that you could get the rail into the U part, where i'd assume you would be getting the maximum field strength (the shape of the magnets could be experimented with). the magnets would also be about 1.5cm wide, so that their spacing lines up with the conductive parts of the second rail.
the main circuitry would be deviously simple. you would need a step-up converter that can step about 3V up to 350v or so. you might think that this would be impossible, or hard, but disposeable cameras have a circuit that do exactly this. (the PSone screen does as well). if nessecary i could make my own (or basically copy the circuit we use in the solarcar). this high voltage would be used to charge some seriously hefty high voltage capacitors, one for each magnet. (im thinking like 1F. *tim allen noise*) but even like 1000uF or something like that would probably be pretty impressive (or not, i really dont know)
the battery gets stepped up and charges these huge capacitors. the capacitors are connected directly to the magnets, with a mosfet switching them on and off (youd need a pretty hefty mosfet), and the gate of the mosfets is connected to the little conductive stretches of rail.
so you drop the ball on the rail, and bring it into contact with the first metal strip. the mosfet opens, and the magnet fires. the magnet itself is an inductor, which will spread the current spike out a bit. hopefully not too much. the mosfets (assuming we're dealing with a ground rail) would be pulled up on the gate pin, so that as soon as the ball leaves the switch mechanism, the magnet would shut off, preventing it from ending up pulling the ball backwards as the capacitor/inductor finishes draining.
...
maybe i will attempt this sometime on christams break. its kidna of a pain in the ass to get it all working together though...
. i was just trying to make it simpler and less dangerous.
