6.5mm Bergmann
Encyclopedia
The 6.5mm Bergmann is an unusual centerfire cartridge produced for very early self-loading pocket pistols. The case is bottle-necked and steeply conical, and headspaces on the conical case walls. Early versions were made without any rim or extraction groove; and relied upon blow-back for expulsion of the fired case from the chamber. Later Bergmann pistols provided an extractor
Extractor (firearms)
An extractor is a part in a firearm that serves to remove brass cases of fired ammunition after the ammunition has been fired. When the gun's action cycles, the extractor lifts or removes the spent brass casing from the firing chamber.-Overview:...

requiring a groove which produced a semi-rimmed case.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK