Originally Posted by nchawkeye

I'd work with sabot and bullet combinations to find a better load...These inlines are easily capable of minute of angle at 100 yards...In addition, inlines are made for shooting sabots and bullets...A round ball barrel will be cut rifling .015 deep with a
1-66 or 1-72 twist in a .50 or .54 caliber...

But to answer your question, yes that round ball load you posted will kill a whitetail...I bought my first flintlock in 1977, a .45 and from then until 1990 I used 75grs of Goex FFF and a .440 round ball...I moved up to a .54 in 1990 and no use a .530 and 80grs of powder...As a side note, I rebarreled the .45 to a .40 and have even taken a couple of deer with the .40 and 60grs of FFF...

When you start going down in power it's almost like you are bow hunting...Limit your shots to 25-35 yards, get tight behind the shoulder and hit them right behind the elbow (low in the shoulder)...