We'll, I'm going to use my 30-06 with a scope. I was worried if one pops out of no where (its happen before) if 1-2-or 3 .45 slugs would take care of it. I'm really looking for a trophy hog, at least 2" cutters. I've always used my shot gun, use a slug in the chamber and 00 buck in the tube in case one decides to charge.
I often carry mine around here with some 260gr soft points loaded to +P levels for just such occasions when I am working around the property. I have shot one thus far and it seemed to work just fine. It was shot through the rib cage and went all the way through the hog. I would have enjoyed the luxury of more fudge factor and been carrying my Ruger Black Hawk in 44 mag though.
Are you talking .45ACP or .45 Colt? Either would do, but you have a little more leeway to shoot heavier bullets in the .45 Colt. With the .45ACP, I would stick to 230 gr FMJ, for better penetration. For frontal shots, that is.