Too hot?

[Patrick Chadwick]

As a rule, BPCR rifles were dimensioned with groove depths suitable for lead bullets. The 45-70 has an astonishingly short throat that is more of a bevel on the end of the rifling than a gradual transition. OK for lead, but it places a much higher stress (=pressure) on the rifle if jacketed bullets are used. Take a look at the Lyman Reloadng Handbook, Hodgdon Data Manual, Sierra Rifle Reloaing Manual etc. They all warn that a trapdoor must be kept to much lower pressures than more modern rifles.

Patrick