Do muzzleloading double rifles follow the same rules for load dev?

[Kynoch2015]

I assume the principles are the same for cartridge vs muzzleloader. I’m starting to develop a load for a ml double rifle. The rifling twist makes it a ball gun, so the projectile is fixed. I assume it’s a matter of finding the charge, maybe granulation as my variables. Any experiences you can share would be appreciated. Thanks!

 

[EBaker]

That's basically what I did with my .50 cal pedersoli kodiak express. It works the best with about 80 grains of ffg. I have a cva express and the barrels on it were so poorly regulated that they wouldn't hit within 5" of eachother at 25 yards with any load. The elevation is way off between the two barrels.