That's great! Don't you love the 32-40!!
I originally worked up a cast load for mine back 11 years ago. I just found the old post with the information on it. I'll past it here:
All of the bullets I used, were from Montana bullet works. Its the RCBS 82024 FNGC bullet sized to .322. That bullet is really for the 32WS, but it was the only one that had a gas check and I've heard from others that it works well in the 32-40 as well. Since the crimp groove is in the wrong place for the 32-40, I just seated all of the bullets down to the max length of 2.50 inches and crimped them good with the lee factory crimp die (that was special made for this caliber). I weighed the bullets and they turned out to be 183 grains. I used new winchester 32-40 brass and cci primers.
I first tried 16 grains of 5744. Those shot fine and read about 1350 through the chrony. Next was 17 grains of 5744 - still good and went through a little over 1500fps. Finally I had loaded some with 18 grains which still shot fine - no pressure signs and shot 1577fps (that's just over 1000 ft/lbs). Accurate arms' literature says you can go up to 20 grains with a 170 grain bullet, but I don't know if I want to go any higher with this heavier bullet - 18 should do the job.
I also loaded some up with 24 grains of 3031 and those shot well as well and ran about 1550fps. I loaded one round with 25 grains of 3031, but decided not to try it that day. Again sources say 26 grains is max with a 170 grain bullet, but 25 grains filled the case completely to the base of that long lead bullet, and I wasn't feeling brave. I might back down and try some at 24.5 first. Although 24 grains is probably plenty.
Now, fast forward to last year. I worked up some Hunting loads with some Hawk 165gr jacketed fn bullets. Worked up to 27 grains of 3031 for around 1900 fps and then killed a nice doe. Here are the original posts with some images if you are interested. again, as I say in my posts, my 32-40 has the nickel steel barrel, so this last load might be too much for BP barrels
https://www.levergunscommunity.org/view ... hp?t=22817
https://www.levergunscommunity.org/view ... hp?t=75541