RE: .45ACP through a .45 Colt?
No- for several reasons.
-The .45 colt uses a .454" bullet while a .45ACP uses a .451" bullet- the bullet would still be undersized but accuracy would suffer.
-The ACP headspaces on the mouth while the .45 Colt headspaces on the rim. You could potentially load .45 ACP rimmed cartridges, but that would negate any reason to shoot the .45 ACP in the gun instead of the .45 colt.