I might try one method that would be to wrap it around a soft iron sleeve aswell, greatly increasing the magnetic field according to wikipedia.
Now I've only started thinking about this stuff today, so could you just charge capacitors by using an electrical cord with seperated +/- wires clamped to the capacitors?
When I get my epic "Gauss" rifle ateast up to about 1k fps and decorated I'll post pics. Now to find a sodering iron...
Thanks guys.