Looking for load data using smokeless with a 320gr cast bullet.

Anyone know of a reputable resource for this type of data?

Somewhere between 68 and 70 grains of 11/2f with a .030 fiber wad should work. Mine likes 69 grains with most any bullet weight/length.

Well, if I would have waited another day to make the original post I’d have had my answers….lol

Was at a friends house and he had a the Lyman #48 load manual which lists smokeless cast bullet data for the 40-70 SS….

In case anyone else is interested…

Use bp and quit fugging with smokeless in it..mb

I've been shooting my Ballard rifles in .40-70 Ballard, which is almost identical to the .40-70SS, for decades using H4198 or IMR4198. It's a very accurate powder, with very little deviation between shots. It also operates at pressures and pressure curves very similar to Black Powder, and often even lower pressures.
My load with a 315 gr. RCBS CSA mold bullet is 23.0 grs., and extremely accurate to 650 yards. For longer 1000 yds. I use the same 18.0 grs. of 4198, but with a Lyman Snover 415 grain bullet. Both of these loads are under 20,000 psi chamber pressure.