You can fire a .45 ACP cartridge through a .45 ACP pistol - and only a .45 ACP pistol. The various .45 cartridges (.45 ACP, .45 Long Colt, .45 GAP, etc.) are not interchangeable with each other.
'ACP' means Automatic Colt Pistol. A 1911, for example, would chamber a .45 ACP cartridge.
ACP means Automatic Colt Pistol. .45 ACP and .45 Auto are the same cartridge. .45 Colt and .45 Auto Rim are a revolver cartridge. .45 GAP (Glock Auto Pistol) is a shorter round than the ACP, and does not interchange with it.
Automatic Colt Pistol
Both. .45 Auto and .45 ACP are the same round.
If it's chambered for the .45 ACP cartridge, yes.
.45 ACP means Automatic Colt Pistol. It IS .45 Auto.
No. The 45 ACP (which means 45 Auto) cannot use the .45 GAP or the .45 Magnum.
If you mean the Glock 36, it's 45 ACP.
It depends. The term "45 rounds" can refer to any 45, and all 45s are not interchangeable. However, I would say that when people say 45, they usually mean 45 ACP.
There is no 45 apc, but, there is a 45 acp. The 45 Colt is a longer cartridge. There is no 45 apc, but, there is a 45 acp. The 45 Colt is a longer cartridge.
The Glock 21 does fire the .45 ACP, as does the Glock 30. You're probably thinking of the Glock 37, 38, and 39, which fire the .45 GAP cartridge - those cannot fire a .45 ACP.