To have a purchase on the rim of the ammuntion.
When the slide or bolt moves to the rear, part of that bolt- the extractor- grips the rim or groove of the cartridge case, and pulls it out of the chamber. At the end of the stroke, another part, the ejector, flips the cartridge out from under the extractor, and out of the gun.
100-200
The first production semi auto pistol was the Mauser c/96 "broomhandle" pistol.
.45 ACP means auto cartridge pistol ( I believe they spelled it pistole though). The .45 auto just means it is an autoloading pistol unlike the revolver style pistol.
.45 ACP means Automatic Colt Pistol. It IS .45 Auto.
Small vest pocket pistol
yes
A fine pistol
They refer to this handgun as the browning model BDA (browning double action auto) pistol.
In order to tell how old your Colt 25 semi auto pistol is, you will need to offer the serial number. This number gives you an idea of when the pistol was manufactured.
It's semi auto not full auto.
Small and inexpensive.