I've been loading and shooting a lot of cast lately. I had forgotten how much fun it was or how effective (Not to mention cheap) they are.
I had a pound of Trail Boss powder but hadn't found a lot of loading data so it just sat.
The other day I was fussing about not having a good bulky powder that would fill my 45/70 cases...So I looked at Trail Boss again.
One fellow I saw said to measure the depth of the case and subtract the seated depth of the bullet. Fill the case to that mark and weigh it. That was the Max load. Take 70% of that and that is your starting load.
That sounded odd so I called IMR....Sure enough, that was correct.
I loaded some 45/70's using Ranch Dog mold 350 gr cast.
I love the stuff. It only gives moderate velocities but that's what I was looking for. It is the cleanest powder I've ever used.
Very accurate in all loadings although, it is a tad better near the Maximum loads.