I believe original ‘coning’ tools were very common and every muzzleloader shooter had one. Today we call the period coning tool a ramrod or wiping stick. I have seen a few original guns that definitely had extensive wear in the bore at the muzzle. Smooth, gradual and even. Some call it coning. Doubt it was put there on purpose by a gunsmith. Have also seen original guns with little wear. Maybe a refresh, or shot little, or maybe a careful owner. It would almost seem to me what we call coning is just another modern attempt to mimic natural aging or wear that occurred over time. Here is a photograph of a ‘modern’ muzzleloader bore with maybe a hundred shots through it, loaded and cleaned with the ramrod and no bore guide according to the original owner. Doesn’t believe in bore guides ‘cause they weren’t used in the day’. How long before this becomes a coned bore? For a modern example, one has to look no farther that WWII vintage guns. The folks that shoot these use gauge pins to determine bore wear at the muzzle. You find barrels that are ‘shot out’ to the point of no rifling at the bore, yet an inch or two down, the bore can be in spec. These guns, because of their design are cleaned through the muzzle (with a sectioned metal rod and no muzzle guide). They don’t call this coning. They call it wear and replace the barrel.