bigcountry

Well, I want both. 450marlin is loaded from the factory I think with pressures in the 43K PSI range cause anything caliber'd in it can handle that pressure. So its cookin.

But you got to be careful with the 45-70. Marlin models 1881 and 1873 Trapdoor springfields should only be fired with ammo in the 20KPSI range. A pre nickel steel winchester 1886 black powder era rifle should be limited to loads in the 28KPSI range. Marlin models 1895 built between 1895-1915 should have loads limited to 28KPSI. Smokeless era winchester 1886's with nickel steel barrel can stand loads from 35K to 40KPSI. Post war lever actions Marlin 1895 and brownings built from 1972 all the way to present can be be loaded fto 43500 psi. You are getting very close to 450 marlin performance at this point.

So bottom line the 45-70 was a blackpowder cartridge and converted. So in the interest of being safe, factory ammo is pretty mild unless noted like garrett and buffalo. But you can handload the 45-70 darn close to performance of 450marlin.