All Pedersoli .45-70s are proof tested for use with the SAAMI maximum of 28,000 CUP ammunition. The late Dick Trenck, US rep for Pedersoli, said:
"Although it is unpleasant to shoot maximum pressure loadings, we do permit the use of ammunition which does not exceed 29007 psi or CUP in these BP Ctg Rifles, regardless of their caliber. This allowable maximum pressure may be obtained using either black powder or smokeless powder loadings.
When using smokeless powder it is the responsibility of the reloader to use only the correct type of powder as well as the correct weight of powder in conjunction with the type and weight of bullet being reloaded.
Use ONLY the printed reloading charges listed by the powder manufacturer and which show the chamber pressure for each such reloading combination.
We recommend the Accurate Arms reloading book #2 (phone 800 416 3006 ) as meeting all our requirements for bullet types, pressure readings and powder charge selections.
Other powder and bullet manufacturers books are equally recommended if they list all the required data."
Manuals differ. Hodgdon goes up to that 28,000 for a few loads in their "Trapdoor" data but most are down around 22,000 or less. A STARTING load with many of their powders will equal or exceed black powder velocities at pressures under 20,000.
Lyman does not show Trapdoor loads much heavier than 17,000 and put the 28,000 CUP data in the "Lever Action" section. A Lyman Lever Action starting load is in there with the Hodgon Trapdoor data.
Confusing, maybe.
I would go in with a medium burning powder at black powder velocity, say a 405 at 1200. If you want more fun than that, there is tested data for heavier loads.
Actually, I only load real black powder in the old calibers, even for modern guns. Truthfully, even that is more than I like for target shooting and my BPCR match guns are .40-65 and .38-55.
