I've killed a lot of deer and hogs with the 45 Colt in a Marlin 1894S and a Rossi 92. I dropped the Marlin in favor of the Rossi, shoot a 290 grain round, flat nose bullet with a charge of Lil'Gun that produces 35.0K PSI and delivers 1775 FPS at the muzzle. The rifle is accurate, has a scout scope on it, and deadly. The longest shot I have taken was on a fairly large feral hog at 197 yards. It ran about 25 yards and folded up in a pile.
The "hole" is the entry wound. A lead round, flat bullet with a good meplat is like a cookie cutter. Cuts a 1" or better hole right through them. I shot this buck at 125 yards.
What single shot do you have? This would be an interesting cartridge to have in that type of rifle.