maple_leaf_eh
CGN Ultra frequent flyer
That is as simple as a zipgun. A stock, a safety operated by the trigger, a receiver and a barrel.
It has a safety! They spared no expense indeed.
But we are already into simplicity over the function, I bet you a muzzle loader with a precision caps is closest thing to a club which can still propel a bullet forward.
Lyman Trade Rifle for instance.
I don't like the exposed hammer though. I would rather go Jaeger 9 for a single shot rifle. Or Ruger No1 - 2 springs and a couple of machined blocks of steel.
Does it only work for shooting people in the back while they run away waving their hands? Instructions images are very precise it seems.
Ya those Gevarm 22s sure don't have much to them.
My vote would be a single shot derringer pistol.