According to modern ballistic experts, a .490 round ball loaded up with 120 gr of 3f Goex, shooting out of a 1:60 twist, 32 inch barrel only has 525 ft lbs energy at 100 yds is incapable of killing a deer.
But we all know that the claim of 1000 ft lbs to kill a deer is horse pucky.

Coincedentally the the same combination only with 80 gr of powder produces 419 ft lbs energy @ 100yds. So for a third less powder there is only a 1/5 loss in energy. But I guess, is still plenty to do a deer in.

Personally I prefer a Volume Powder Measure vice the palm of the hand method.