No reason why it wouldn't .A lot of powders will work. But, that said, for reduced loads with an easy to ignite powder, spring for some 4198, either IMR of Hodgdon and keep you life simple.
Hey, I really want you to pursue this 458 with 45-70 equivalent loads thing.... not that it's any of my business. I have owned a couple of 45-70's....an early 1972 vintage Marlin 1895 and another Ruger No. 1. Both rifles shot well and I used them for several years very successfully, but came to the conclusion that getting kicked out from underneath my hat every time I pulled the trigger was losing its appeal. The heavier No.1 with 45-70 loads is a whole lot of fun to shoot and it's also easier to shoot accurately than the the lighter 45-70's. Actually, a LOT easier.
My rifle which is pretty much identical to yours, shoots like a damn match rifle with 300 grain bullets at 1900 to 2000 fps. Five shot groups right around and 1". There is something very satisfying and impressive in looking at that cluster of 45 caliber holes in a target.
Last edited by meddybemps; 12/03/18. Reason: Adding words of encouragement.
