Just a question to experienced shooters

Dwight Gruber · 04-30-2006, 04:37 AM

Billy,

You have made a good observation. This is normal, and is a designed-in feature of the gun.

The 9mm Parabellum cartridge is not cylindrical, the straight sides are slightly tapered. The Luger chamber is bored as a cylinder for about three-quarters of its length, then is bored cartridge-diameter and -taper to the chamber mouth. This leaves a slight 'step' or ridge in the chamber. The purpose of this ridge is to form a gas seal at the moment of firing as the cartridge case expands to conform to the chamber, thus keeping most of the chamber free from powder fouling which would affect ejecting and chambering.

You can see the slight ring in the chamber of this cutaway Luger

--Dwight

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04-30-2006, 04:37 AM	#2
Dwight Gruber User Join Date: Jun 2002 Location: Portland, Oregon Posts: 3,908 Thanks: 0 Thanked 1,330 Times in 435 Posts	Billy, You have made a good observation. This is normal, and is a designed-in feature of the gun. The 9mm Parabellum cartridge is not cylindrical, the straight sides are slightly tapered. The Luger chamber is bored as a cylinder for about three-quarters of its length, then is bored cartridge-diameter and -taper to the chamber mouth. This leaves a slight 'step' or ridge in the chamber. The purpose of this ridge is to form a gas seal at the moment of firing as the cartridge case expands to conform to the chamber, thus keeping most of the chamber free from powder fouling which would affect ejecting and chambering. You can see the slight ring in the chamber of this cutaway Luger --Dwight