With some exceptions, the majority of common automatic pistols have a feed ramp. They have to have one because the ammo is fed from below and behind the barrel and its chamber. In the feeding and chambering cycle, the fresh cartridge moves forward and up to its place in the chamber. This is a simple invention that has been used since the very first pistols. More often than not, a small portion of the chamber mouth has a radius to form this feed ramp. This creates a small crescent of surface of the cartridge that is not supported by steel chamber walls. In firing, this area takes the full pressure for just an instant. But it takes the pressure at the head of the cartridge where the brass—a wonderfully elastic material—is thickest and strongest. Literally, billions of rounds of ammunition have been loaded, fired, extracted and ejected from typical pistols since the first one was fired.
June 11, 2012
