45-70 black powder recommendations

[MtnMike2]

I load BP cartridges for my Win Mod 1886. You can't get 70 gr of BP into the modern cases - it's my understanding that the old cases had thinner walls and were a little bit bell shaped. Some folks use a drop tube which will get a little more powder in or you can try vibrating the case once you have powder in it. You shouldn't compress black powder though as the burn rate is then unpredictable (unlike smokeless).
I have used duplex loads in the past. Refer to Loading the Black Powder Rifle Cartridge by Paul A Mathews, Wolfe Publishing Co, 1993. Many folks will tell you not to do it; that is, to mix BP and smokeless as they think it dangerous. But the idea is to get a more clean burn so you can make multiple shots without cleaning as BP is inherently "dirty". But supposedly back in the good ole days they were better at making cleaner powder. Anyway, you use only a very small amount of hot pistol powder with your BP or BP substitute. I'm reluctant to put my load here but it worked fine for me. I use Pyrodex BP and Beartooth 405 gr Gas check lead bullets w/ SPG lube. The muzzle velocity is very low. Because I'm using GC bullets and the powder fills the case, I don't use wads or spacing material. I was able to get 6 shots without cleaning.
But my latest BP load for the 45-70 and the one I recommend uses Black Horn BP substitute. Same bullet. For load data, go to http://blackhorn209.com/files/pdf/b2...tridgedata.pdf. My current load is 38.0 gr of BH 209, CCI C250 primer. Chrono'd at 1290 fps muzzle velocity.
Good luck with it! Let us know how you do.

^^ Mike