Klikitarick-I hate to disagree with you as I don't know you.But not all data is documented as Hodgdon is.First off the .450 Marlin factory ammuniton was tested at 41,900 PSI and 2028 fps in the Guide Gun.As you know the SAAMI pressure for the .450 is 43,500 PSI.So all the loads you listed are under maximum pressure.RL-7 is famous for higher velocity and less pressure in the 45-70.The 45-70 and .450 Marlin are two pea's in a pod when loaded with the same bullet and powder except the .450 Marlin has less case capacity.The Winchester 45-70 brass hold's seven more grains of powder than the .450 Marlin brass when filled to the brim. Some loads tested in a test barrel from Rick Jaimeson with the 350 Hornady out of the guide gun.
58 grains of vvn-133- 2052 fps with 41,400 PSI.
58 grains of aa -2520-2041 fps with 40,200 PSI
Speer 350 grain
67 grains of aa-2520-2063 fps with 42,000 PSI
51 grains of H-4198-2025 fps with 40,400 PSI
The examples you listed were all within the 43,500 PSI or 40,000 CUP.Not all manuals are the same.Hodgdon's is the only one I would use to load a max charge as there's are documented according to Jackfish.
I bought two boxes of Buffalo Bore's 350 grain Speer when I got my 45-70.It chrono's out of my guide gun at 2114 fps.I don't know if it's the same lot,but It's posted at 39,500 CUP.Within the limit's of the modern 45-70 according to Hornady who was the first I know of to put it out the modern 45-70 can handle 40,000 CUP in 1980.
Just my opinion.Jayco.
