Ammo
Which .45 are you referring to? .45 Colt, .45 Schofield, .45acp, .45 magnum?
I believe we all understand that nothing is fail safe where ammo is concerned. I do, however, have a little difficulty absorbing your "fact" that a 12 gauge failed to stop a person with a chest shot at 5 feet.
I will personally attest that a .45acp is pretty good and dependable for a handgun. My late Father gave me my first 1911 when I was 12 years old and I have carried and used the round since. For many years I carried a 1911 Government Model and Combat Commander on duty. As long as you don't ask it to do everything it is dependable.