Bob is a very good friend and good shooter as well.
We've been shooting Black Powder and Conicals of this weight with percussion rifles for nearly 30 years, only recently putting that 1800's technology (45 1:20 twist) into these in-lines. Just ask Knight here in TN what they've learned. Yes, trajectory is more with the heavier bullet and lower velocity, but that's relatively easy to adjust with the scopes & technology today. Energy remains at longer ranges more than lighter faster ML, they actually cross much earlier than I expected when comparing data (see graph). Their weight even resist wind drift better than light/faster.
Here's the actual bullet being shot that I made quite a few years ago - it has killed dozens of deer by multiple hunters, nearly to 500yds. Cost about 5 cents each to cast.
It was used to win the 1st NMLRA National Championship as well as set a few National records on paper.
You might have to click on the photo to enlarge, but I did this a few years ago when Remington came out with their 300yd Ultimate ML. Yes, their 1200 ft-lbs at 300yds is enough energy to ethically kill.
Good shooting my friend!