I was only semi-kidding with my reply up above. If I had an interest in using a powder I thought should work but had no proven data I wouldn’t hesitate to set up a remote control chronographing system with an expendable rifle, but many these days are reluctant to experiment…
For hot rod.45-70 loads I’ve used Varget for years with good results. As mentioned above, 4198 is often recommended as well. I’ve no experience with TAC, but it must be close to those two, I would think.
