Feed ramp
Feed ramp is a basic feature of many breech loading cartridge firearm designs. It is a tightly machined and polished piece of metal which guides the cartridge at the top of the magazine into the firing chamber of the barrel. Depending on design, the feed ramp may be part of the magazine (AR-7), part of the receiver or frame (Mauser C96), or part of the barrel (H&K USP). However, some firearms, like the FN Five-seven, have a beveled chamber instead of a feed ramp.
The feed ramp is a critical part of an semi-automatic pistol or automatic rifle. When the pistol is fired and the spent case is ejected, the feed ramp functions to direct a fresh cartridge from the magazine into firing position; that is, the slides along the feed ramp into battery. The need for the cartridge to slide both forwards and upwards along the feed ramp and into the barrel is the primary design consideration that makes the ogive the preferred shape for all modern automatic pistol rounds (a hollow point bullet is a truncated ogive), as there are many other shapes that are stable in ballistic flight.
The feed ramp is a common point of mechanical failure that leads to a "jam" of an automatic pistol. A rough surface or the presence of debris on the feed ramp will eventually lead to the bullet being directed off-center, causing the gun to fail to complete the reloading cycle. Polishing a feed ramp is among the tasks commonly performed by gunsmiths.