I have read with some interest that you can use some size of buckshot as a substitute for round ball in a .32. Does anyone have experience doing this? Where do you source your shot (and what size)? Thanks
When it comes to patched, round ball...,
You could use #1 Buckshot that was lead alloy for a .32 rifle, as it's .300, coupled with a patch. You might find that if you need a thin patch, that a little corn meal between the patched ball and the powder reduces burn-through. You should use a micrometer to double check the diameter when using the commercial, alloy shot.
(Some folks with .36 caliber rifles have had success with 00 Buckshot and a thick patch in their .36 rifles. As long as the patch and ball combo is tight enough to impart a spin, you should do fine) Remington #1 Buckshot
Most of the folks doing pre-made buckshot in black powder, from the ones I've met and the ones I've spoken with online, are using the stuff in black powder revolvers. They are using 00 buckshot in their .32 pocket pistols (as it's .330 diameter). Further they cast their own out of a 00 Buckshot mold with pure lead, not commercial made buckshot. The commercially made stuff is normally hardened with antimony, so is a lead alloy, not meant to deform when launched from a modern shotgun, so it's too hard for the little loading lever on most .31 revolvers to swage into the revolver chamber.
The problem you might have would be finding a #1 buckshot mold, as the popular sizes are #00 buck, #0 buck, and #4 buck.
Hornaday used to sell .320 buck shot ()-buck) in 5# boxes. You can also order from Ballistic Products 1.5buck which is .315 I believe. I just cast my own balls (.311) from a Lee double mold. One of my guns prefers almost bore diameter balls. I have a .319 Lee mold I use for that gun with a 0.18 patch.
Ballistic Products' Super-Buckshot (shown) is extremely round with a class-leading antimony percentage for buckshot pellets -- 3% on a per-pellet average! This antimony content makes our Super-Buckshot harder than even some plated buckshot! See Ballistic Product's BUCKSHOT MANUAL for hot loads...
I have a box of Hornady #6411-1 buckshot. If I read the label correctly, that is 000 shot, .300 diameter. This does not appear to be available anymore, however I did find some from Ballistic Products in 8 pound jars.
I use a .10 prelubed patch, and 25 gr. 3f goex. Very accurate out to about 25 yards, head shot on a squirrel using a rest.