Hey smokehouserex,
not tougher, thicker recoil pad, and I do not shoot it off a bench!
As for "Trapdoor loads"
Hornady says 25,000 cup, Sierra does not list the pressure, but recommends only 300 grain bullets, Speer lists 28,000 cup (and says this is factory ammo pressure level), my Lyman manual keeps loads under 20,000 cup, Accurate Powders shows 28,000 cup, Hodgdon Powders shows 28,000 cup, Alliant does not list a pressure level, IMR does not list a pressure level, Vihtavuori powders shows 28,000 cup and psi, Barnes Bullets shows 25,000.
So one 20K, two 25K, three plus factory at 28K, and three not listed. That's all my data on Trapdoor level loads. Since the factory ammo makers see fit to trust 28,000 cup (psi) I would not be afraid of any load at this level, or below. The .45-70 is a very forgiving cartridge, and does not show pressure signs until grossly overloaded and stressing a Ruger #1. Things to watch for with your rifle are excessive recoil, louder than normal report, and powder marks around the primer.