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.
Last edited by marlinguy; 03/19/24.
