This procedure, in the present day is known as "coning". ie a "coned" muzzle. It was known in the 19th century as "relieving", ie; a "relieved" muzzle and also as "funneling", ie a "funneled" muzzle. There is very little historical data written about this as the gunsmiths' apprentice was taught the "hands on" method and not from a text book.
When these "hand taught" barrels makers passed on all their secrets died with them. I have examined many original m-loading barrels and there is definately a "funneling" at the muzzle. Some historians thought this "funneling" might be ram rod wear but that does not appear to be the case. One of the most interesting quotes on this subject is that of the famous Bill Large (now deceased). Bill was one of the founding Fathers of the NMLRA and one of the earliest 20th century barrel makers who helped pioneer the resurection of the m-loading rifle. Bill Large barrels are coveted today. In a letter to John Baird who wrote "HAWKEN RIFLES, THE MOUNTAIN MANS CHOICE". Bill stated that he had re-bored and rifled 25 to 30 original Hawken barrels!!!!---- He also stated---"all were belled and showed signs of the funneling tool commonly used by most gunsmiths, as a request of the owner, to permit easy and fast reloading"""".
I first began experimenting coning muzzles when I heard that these tools being made as "caliber specefic",ie; you had to have a seperate tool for each caliber you wanted coned. These caliber specific tools had a slow taper and removed a LOT of rifling deep into the bore. I wondered how much of the rifling HAD to be removed, and at what angle it had to be removed "to permit easy and fast reloading", thus eliminating the use of a short starter.
I then handmade some protoypes out of different materials, just to see if it really would work---AND IT DID!!! I hand made many tools over the last couple of years and I changed the specs. slightly each time to make it more universal. I finally was satisfied enough to go the the lathe and produce some out of pure yellow brass. Now you need only ONE TOOL!!!! This coning tool will work on those little .32 cal squirrel guns AND up to the big .75 cal "bore" guns by using YOUR CORRECT size cleaning jag..
Insert tool into barrel and mark depth
Make a paper pattern of at least 2 1/2 inches long
Align paper at mark and overlap it at least one quarter inch.
Start with coarse 150 grit paper.
Use you preference of adhesive and align paper with mark. I have used 3M spray upholstery adhesive (expensive) or a thin coat of rubber cement (much cheaper). at times a thin strip of duct tape will help at top and bottom.
Wrap paper counter clockwise looking at threaded end of tool.
Paper glued and tap handle installed.
Use your proper size tightly patched cleaning jag to center the tool in the barrel. This tool works great on crowned barrels and can also be used on fresh cut offs by lightly crowning the barrel, just enough to get patch and jag started with out tearing.
A drop of WD 40 helps keep the paper cleaner for a smooth cut, just a little though as you don't want it to soak through the paper and soften the glue.
First cut. A little duct tape helps at times.
Second cut, move the paper up tool till a clean area of paper contacts the bore and cut again.
Third cut, moved paper up and cut again.
Notice how the cutting patterns keep getting longer.
Cone till the rifling just disappears at muzzle.
Switch to 320 grit and polish with fine.
When you are finished you will see a short section where the bottom of the lands are polished. This should be enough to get you loading easy but if not satisfied after testing then go through same procedure again.
Thank You for taking the time to read my Tutorial, Ed Hamberg,,, (Longknife)