I tracked him and shot him several times with a rifle. He kinda got stuck on a couple rocks and was running back and forth while I took shots. There was blood to confirm the shot but no blood trail. He's probably unkillable.
In my experience fiddling with loot settings recently, the revolver keys off "baseline resource availability" along with hatchets and knives. It has to be set above "low." Only the rifle is affected by the "Rifle" custom setting.