ORIGINAL: statjunk
Talked to Tommy at Leadheads. He claims there is no need to do anything but the following.
300gr bullet use 51gr of IMR 3031
425gr bullet use 40gr of IMR 3031
Any mention I made of trying something else he says will be a waste of my time. I find it hard to believe but old buggers are rarely wrong. I'm going to try that set up. This is the first time I wished I had a Chrono.
Tom
That sounds good but every gun is different. But if I was you, I wouldn't hesitate to try 40, 42, 44, and maybe 46gr. My 45-70 starts stringing shots vertically at the higher loads. But know other where their guns require the higher pressures.