Load help for 225 grain 45-70

[badguybuster]

I picked up some 225 grain projectiles but cannot find load data for them. And before you ask, yes they are .458s. I found a couple loads but they use IMR 4198 and RL7, neither of which I have or can find. I do have H4198, H4895, IMR 4895, Unique (i know 15 grains will work for a mild load but leaves a lot of empty space), 3031, Benchmark and quite a few pistol powders.

Fyi.....these are the dreaded J word

[pworley1]

The starting load data for the imr4198 will work fine with your h4198.

[badguybuster]

I wasnt sure about the difference in the burn rates.

[Conditor22]

If you use the starting load any difference between H and IMR are safe to shoot

https://www.lehighdefense.com/product

[John Boy]

The 225gr bullet is not common for the 45-70 but work down the load from here using a mathematical calculation and start with a 10% less charge .. http://stevespages.com/458_1_250.html