In an 1895 GBL I know, 36.2 grains of IMR4198 under a plated Campro 300 grainer offers cloverleafs at 50 yards.
The slower IMR3031 would be better suited for 400 gn projectiles.
After depriming, I toss the brass in a pickle jar of warm water with Dawn and Lemishine overnight.
Clean enough.
My OCD demands annealing every time.
I've only ever seen OTHER people's brass split.
.45-70 brass ain't cheap.