Over time, I found I prefer to use heavy bullets at a lower speed in the .45-70. I generally use 405 or heavier.
If you want to use 250 or 300 gr, you will most likely find you need to push them around 2000 fps or faster. I like 4198 for this
Every barrel is a bit different. As I recall, for my guide gun, 50gr was the sweet spot for both 300gr around 2000fps and 250gr jacketed bullets somewhere around 2250fps
Last edited by Frontiersman; 01/15/18.
