Partner to the Vostok pistol sketch from way back. I've been playing a lot of Fallout 3, so I think that must have influenced me.
It's an energy weapon, but uses capsule-like ammunition. Each capsule can provide up to 300 pulses before it burns out.
Surprisingly large recoil is absorbed by rotary spring connected to double dampers, one above and one below the central barrel.
(The rotary damping idea is my own, but I recently discovered that the French beat me to it, with the limited-production MGD-PM9 sub machine gun of WW2.)
The weapon is handed out to the citizenry; every worker and farmer has one stowed away somewhere for use in the event of conflict or a call to military service.