I'll second the Supertrapp system :)
I Screaming Eagle Nightstick is a rebadged Supertrapp.
The Supertrapps' have an open end-cone option as well as the closed cap, you use less discs (10 or 12 if I remember correctly) and it is louder than the closed cap, and some people say it will pull harder faster, I have a closed cap and I think 20 discs in my 103.
Good Luck