Just my opinion but, these old style pistols were made for offense and defense against other men and occasionally as a last resort for gathering food.
Against men and small game they worked rather well but I seriously doubt that they were used to shoot deer on a regular basis.
My dad taught me to never use a underpowered gun to shoot animals which explains why I would never think of shooting a deer with a .22 RF or even a .22 RF magnum.
For the same reason, I would never shoot a deer with a black powder pistol unless it was to put down a already shot deer at point blank range.