I'm going around the horn on finding data for my 43 Spanish. My major concern with this old rifle is pressure as it's a BP rifle. A data sheet I got from a member here lists AA8700 data of about 56gr or so of AA8700 but notes that this is a 45-70 loading minus 10% for safety. There is no pressure data listed. I have some, well maybe 40lbs, of WC860 which Jeff recommends using AA8700 data with.
I looked up an old thread on this site about 45-70 and AA8700 and found this loading:
420gr. (Ly 457193) 54.0 8700 1025fps 60.0 (Max trapdoor) 1165fps 11,700psi (compressed load). 24" test barrel
The pressure sounds fine to me as it's in the Black Powder range but I would like opinions on this. Safe load for the Rolling Block?