Thanks for the load info Ranch Dog. Yesterday, I finally had the chance to get out and try some of your suggested loads. I was very impressed. The recoil was stout. I would compare the recoil to my Mossberg 500 18"bbl with slugs.
This Rio Grande is my first and only 45/70 (although I do have a Ruger No. 1 to pick up Friday). I really like this gun. The action is very smooth.
The loads I tried were:
50 gr. X-terminator w/ 350 gr. Laser-Cast.
56 gr. H335 w/ 350 gr Laser-Cast. This was near your max load of 56.7 grains.
These were powerful!
45 gr. X-Terminator w/ 405 gr. Missouri Bullet.
and a load of my own- 37 gr. H4198 w/ 350 gr Laser-Cast. This was mild compared to the above.
On the 56 grain load mentioned above, I did see what I think are some pressure signs, see the picture. I don't know if this is enough to be concerned with. I would like to hear your opinion. The case on the right was the 56 grain load, the left was one of the 37 grain loads.
Again, thank you for your assistance & advice
SoCal44