I don't know about .45 Colt but when I was 18 I bought a .44 Spec. and my 15 yr. old brother had a single barrel .410 and we shot several of the pistol shells in the shotgun. We didn't have any .410 slugs and we figgered that big bullet flopping around would do more damage than #6 shot. We never shot an animal so we don't know for sure. A .38 S&W with a wore out barrel that throws the bullet sideways will shoot through a 2 in. beef roast and a 1/4 in. piece of plywood at 10 ft. Larry