I ended up going with this load for ML season:
.45 cal saboted bullet (.50 cal rifle), 240 grains, Hornady HP, over 100 gr of Blackhorn 209. I first sighted in with saboted 300 grain bullets over 110 grains of BH209 and it knocked the crap out of me (jiminy!), but then ran out of those bullets before I could get a satisfactory group. I was more than happy to switch to a lighter one. The 240s weren't grouping right with 110 grains of BH209, so went to 100 and it shaped up to "good enough".
I shot a few of my "nested sabot" 195 gr .357 bullets in two sabots, but the opening on the end of the bullet seating attachment to my rod wasn't wide enough, so after seating the load, the rod end grabbed and pulled out the plastic ballistic tip from the Precision brand bullets. Which would be all well and good if it would do it EVERY time, but it didn't and there was a 10" POI change between tip and no tip at 85 yards. So I had to abandon that load for now.
I love BH 209. I didn't even clean the ML after the long range session. After I sighted in, before leaving the range, I loaded one last load (sans primer), and left it in there with fouled bore - ready to hunt; just add primer.