Make Berdan ammo from 43 Spanish by necking down slightly ,fireform and use .429" bullets.
Is this something you have actually done and it worked well for you? I've seen this advice repeated many places on the internet, but it makes me wonder because...
I have tried the 43 mauser brass in mine and it won't extract - extractor slips. Ended up getting berdan brass made from starline 50-110...