Perhaps it's something like the power guns used by Hammer's Slammers.
In the Hammer universe, a powergun is a weapon which projects high energy copper plasma toward its target. This plasma is created by inducing an electrical field in a precisely aligned group of copper atoms; the atoms' alignment causes a resonance which greatly amplifies the field energy and ionizes the atoms. The resulting plasma is directed by a firing chamber and barrel made of refractory metal, such as iridium; the chamber and barrel are cooled between shots by injected gas (typically nitrogen). The copper atoms are stored as individual charges, with the atoms held in the correct alignment by a plastic matrix which is mostly consumed by the firing. All the parts of a powergun require extremely precise machining and advanced materials, which makes powerguns very expensive; ---Wikipedia.
If I remember from my reading a long time ago, the 'bullet' is a thin round wafer, something like a thin mint.
BTW I've heard that the road to hell is paved with thin mints so that would make sense.
