I was lusting over a new 1911 just yesterday. As I am an ignorant son of Texas, I am certain that you know better.
I will them explain the differences between the cartridges .45 ACP, .45 Auto, .45 Auto+P and Cartridge, Caliber 45, Ball, Model 1911.
Hint: They are four distinctly different cartridges, manufactured to four distinctly different Technical Data Packages, tested with three different pressure measuring systems and specifications.
Just because cartridges appear similar to laymen doesn't mean they are interchangeable. Please read the warnings on every box of ammunition manufactured by SAAMI affiliated members or other responsible company about matching the head stamp to the exact caliber designation marked on the pistol.
And please do not waste your and others time by seeking out and listing the few irresponsible companies (and most gun writers) that violate protocol or are too ignorant to know the facts.