The 43 Basic brass is around 3" long and needs trimmed to 2 1/4 inch (57mm) They use about a 400 grain bullet, BUT a regular round nose bullet usually won't work. They need a tapered "Semi-Spitzer" slug. Weather you use paper patch or regular lead hollow base bullets, you need a "Cookie" of lube under the bullet 1/8 to 1/4 inch thick (SPG or paraffin/Crisco mix work fine), and an over the powder card of fiber, felt, or cardboard (milk carton). The solid web modern brass won't hold as much powder as the old Balloon head cases, so a 65 to 70 grain charge of FFFg or FFg will have to do. I have the Spanish predecessor in 43 Reformado. Just about the same except for .454 diameter bullets!

Once you have correct brass for your Rolling Block, you won't absolutely have to have loading dies. You can reload without sizing the neck is the chamber isn't too loose! Back between the wars and shortly after WW II it was common to use a large bench vise to "Press" the round together, and being a single shot a crimp isn't necessary except to keep the round together if it falls over. I have 43 Spanish and 43 Reformado dies from C-H 4-D in Mt. Vernon, Ohio, I have their shell holder also (it fits the 11mm Mauser round too). WLR primers do a really good job; not too little/ not too much for the black powder rounds. Brass and ammo are listed in midway's catalog (If not on B/O) The 44-77 BN and other brass will work too but usually costs more. 348 Win brass is considerably larger at the web and will destroy you 43 dies if you try to just size in down. (Sometimes the chamber is worn or modified to use neck expanded 348 Win brass, but it is about 3/8" short!)

Ivan