One thing you might try is a hardened roundball. Pour some balls up with added wheel weight. See if your rifle likes them or not.
The hardened ball will travel thru more of the elk, in case something unforseen happens. Elk have big bones and huge muscles, plus a tenacity for life.
My GPR loves...
120gr of FF 777
.005 lubed patch
Lubed wad between powder and ball
Some WW added to the roundball
My rifle must be weird, because it goes against most BP advice.
It doesn't mind the hardened ball.
The more powder, the tighter it groups.
The .005 patches shoot better than the tighter...
Used to BP elk hunt up the McKenzie, but elk were getting harder and harder to find. Knew I had to do something different. Last year we headed east. It was a big learning curve, but can't wait to get back to the Strawberries again.