Powder Question

[Willie Bean]

Working up loads for a 224 Valkyrie load data has IMR4198 listed looking at the burn rate chart H4198 is listed next to it, if I start at the starting load and work up watching for pressure signs I should be O.K. my question is has anyone exchanged these two powders before?

 

[MN50Shooter]

Even though they are next to each other on the chart, they are similar, but do have a small differentiation in performance. If you change from one to the other, I suggest starting low and working up to a load that both, meets your expectations in speed & accuracy, and are still safe.

I do this even with the exact same powders, when I change from lot to lot. I will ad the caveat, that the majority of my accuracy loads are above most printed max charges. Each one, is tuned to a specific rifle, case, bullet, powder, primer combination. Change anything, and I reduce my charge and begin all over.