Ben 51 gr of r-l #7 ? "What kind of psi signs where you getting?"
Read Ben's post again.
He plainly stated it was shown as 28,000 CUP, about 70% of the pressure your Marlin is designed for.
Be a little careful of Reloder7 data as there is a lot of data around for the Hercules version of Re7. When Alliant bought them the powder changed a bit. You need 3-4 gr less powder to achieve the velocities listed for the old loads.
Chris.

You didn't read it here but, my pressure limit for the modern Marlin 45/70 is the same as the levels of the same rifle in .450 Marlin, .338, etc. and all are with cast bullets.
1700fps and below 28000cup, I've used 51 grs. with 420 gr. cast for hunting with the Marlin.



























