I tapered three of my own. It's not hard, just takes a razor plane and a bit of time. Get a few hickory rammer blanks from Track of the Wolf. They have them with threaded brass or steel tips, or plain. Keep the worst full length for cleaning at home and taper the one(s) with the better/straighter grain (no run-out).
Set the plane blade to the thickness of a paper dollar. Draw a line around the rammer 8" from the muzzle end and then draw two more lines equally spaced for the balance of the rod. That is, if the rod is 44", with a ring at 8" back leaves 36", so draw lines at 12" and 24". The inside diameter of the first thimble may force you to start the taper beyond that if it is smaller than your dowel stock. Better to start larger, of course.
Now, starting at the 12" make one cut from just above the pencil line to the tip, tur the rod a few degrees and repeat. Do this until all the pencil line is shaved off. Now move back to the next pencil line and repeat. And finally repeat at the third line.
Then stain the rod, burnish it with the shaft of a screwdriver or antler tine, stain again and seal with the finish of your choice (boiled linseed oil or even just paste wax).
You can use a small plane or an X-Acto razor plane. I have one of Dean Torges' Bowyer's Edge spokeshaves for tillering bows or tapering arrows and it works perfectly.
I have found a tapered rammer works better as a short starter (just choke up to the last few inches of the rammer. I made one with no fittings that I use with a tow worm for truly authentic cleaning, two to take either a threaded tow worm or jags for general purpose and the original tapered rod my rifle came with.
And it is some unwritten law that if you have two spare rammers you will never break one. :wink: