I have no experience with the 325gr. Hornady. I have heard it is a big soft for really fast loads. I don't know. If it is as heavily jacketed as the 350gr.RN, it should do just fine as that bullet worked well for me on moose.

In an action capable of handling 40,000, I'd probably use somewhere around 54.0gr. H4198 in a .45/70 - which is listed as 39,300CUP. But FIRST, I'd start at around 48.5gr. listed as 32,200CUP at 2,036 fps and work slowly, using a chronograph and watching for any pressure signs, all the way.

With that weight bullet I do not believe the .45/70 case has enough room to produce those higher speeds with slower burning powders,as with the 350gr., compressed 60gr. plus loads are shown at barely over 2,000fps.

Do purchase Hodgdon's Annual Mannual.

It's .405 Win Loads include 400gr. Woodleighs and loading data to 2,400fps for the 300gr. Hornady.