Wow! That video is superlative!
I have made a number of tapered ramrods, but mine normally have a tapering swell at the head, a parallel or untapered body, and then a taper at the last five or six inches to facilitate clearing the forward lock bolt. Larry's ramrod appears to have a uniform or progressive taper over its entire length. However, the 2x2's with sandpaper glued to them, to use as a tapering tool, is brilliant, and I can envision how it could be adapted to make the type of rod I have made. I have a length of pine 1x6 tongue and groove lumber that I clamp in a vise with the groove up. I lay the rod blank in that and taper it down with a block plane. This technique has always worked for me, but if I were to make very many tapered rods, I would probably make a gadget like Mr. Potterfield used.
I don't have the equipment to make the brass end fittings. One thing I have learned to do when installing threaded ferrules is to put some grease on a 3/8" machine screw in 8/32 or 10/32 (as appropriate) and put that in the threaded end of the ferrule before epoxying it on. Otherwise, you can get epoxy in the female threads, which is kind of a pain to clean out. Just don't forget to put a dab of grease on the very end of the screw!
I drill the hole for the crosspin .002" - .003" undersized, then enlarge it to the same size as the pin in the metal ferrule only. I use a toothpick to put a little epoxy in the hole before driving in the pin. After the epoxy is cured, I cut the pin and file it flush, but I've never found it necessary to peen the ends. I've never had a pin come out.
There are a lot of ways to skin this cat. Mr. Potterfield's video was very informative.
Thanks!
Notchy Bob