I have no experience at all shooting humans (thank God). But I've shot many animals over the many years of my life. Never for no good reason BTW. I've had to shoot my share of feral dogs. They can be a deadly problem. I shot one dog point blank with buckshot. It didn't die. I had to shoot it a second time. I've shot several dogs in the brain. They all die from that but not always instantly. One of the worst experiences of my life involved shooting a feral dog with a SKS. I didn't miss but the dog turned it's head slightly just as I shot. I won't go into the details but it took hours for that dog to die. It jumped up and ran off after the shot. I'm still sick over that. I just don't miss when I shoot to kill. Only twice in my life has that happened and both times involved movement as I shot.

The point is though that you just don't know what it's going to take to actually finish off a human. Killing anything is not pleasant. Shooting a human doesn't come natural to anyone except a rare few. You want the shot you take to count as much as possible so you don't lose focus and forget why you shot in the first place. It makes me sick to think of doing it. But it makes me more sick to think of the consequences if I don't.

Bird shot is for birds. A 9mm is NOT equal to a .45 I don't care how many people say it. I've shot both too many times. A pistol round is not as effective as a rifle round but it may penetrate a wall more than a 5.56 round. My wife can use my AR much more effectively than she could my 12 ga. shotguns. Those things are just true. BTW other pistols can be much more effective than a .45. Use the biggest one you can handle effectively especially regarding followup shots.