The charge dart rifle was taken from the design of a sniper rifle, only the muzzle of the barrel was modified so that it was longer and only made a "spitting" noise when fired. The Dart would be a small, barbed metallic bolt (which would be pretty painful to pull out when it is inside someone) with a long coil attatched to it (about 15 feet long) which could be reeled in like a fishing rod after being fired.
When the gun fires, the dart is propelled out by a bronze-spring which is clicked into place by the hammer on the back of the rifle, above the butt of the gun (which actually works as the power source, with a hatch housing two golden power cores that feed the shock-current). When the coil is reeled in, the spring sets itself into place again, but requires re-priming to actually fire the dart again. The Charge-Dart Rifle has an awful cycle rate, taking about thirty seconds to reprime (including reelage time) or five minutes to reload (because the dart has to be threaded into the coil), but the power the weapon packs against a singular opponent is not to be sneezed at.
The shock coil works in sort of the same manner as goblin jumper cables, except it gives a reverse affect, defibrillating the unfortunate who is strikes. The shock coil has certain voltage settings, but is prone to exploding or running out of power too quickly on a deadlier setting. Janek mostly uses the rifle on "stun". Rather than killing someone, he will give them a chance to surrender before feeding a higher voltage charge through the coil.