For a Ruger .45, 7-1/2" barrel-- a .457, 190 grain Buffalo conical pushed by 40 grains of Pyrodex " P" yields a muzzle velocity of 1157 fps, with 565 fpe.

That 565 ft. / lbs. of kinetic energy at the MUZZLE is well short of the minimum 800 fpe required to cleanly harvest deer, not even close. At 25 yards, you are down to 485 fpe.

You might want to do the deer a favor, and leave it at home.