Someday I hope to get my hands on some Black Mag 3. If it wasn't for the Hazmat charge, I would have some now . . .

It has been my experience, with the Powerbelt bullets, that there is certain window of pressure where they work the best. Too little and bullet doesn't upset enough to fill the grooves. Too much, and the stem at the base of the bullet deforms enough to give inconsistent release of the skirt - and accuracy suffers. (This is my theory and not offered as a scientific fact).

With Pyrodex RS, accuracy for me started falling off below 90 grains. That's why I tried the T7 FFFg. Got down to 75 grains before the groups opened up. And I think the recoil of this load is a little less than 90 grains of Pyrodex.

Still I wonder about the Black Mag 3 . . . . .