Just a question to experienced shooters

B_Connor · 04-30-2006, 12:16 AM

About one month ago I was given an Luger 9mm parabellum by my father that was passed onto him from a dear friend of our family who was a combat veteran of WWII. This gun was in the box never fired. From what I can gather, it is a replica made between 1975 and 1978 by Mauser and distributed by INTERARMS. Some of the writing on the gun (e.g., on the safety) is in German.

I have shot 100 rounds through my Luger and am hooked. However, I ave noticed that on every expended case there is a horizontal indentation abot 5 m long about 5 mm below the rim of the casing.

Is this normal or does the pistol need some type of adjustment?

Thank you kindly,
Billy

Dwight Gruber · 04-30-2006, 03:37 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

04-30-2006, 12:16 AM	#1
B_Connor New User Join Date: Apr 2006 Location: Orofino, Idaho Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Just a question to experienced shooters About one month ago I was given an Luger 9mm parabellum by my father that was passed onto him from a dear friend of our family who was a combat veteran of WWII. This gun was in the box never fired. From what I can gather, it is a replica made between 1975 and 1978 by Mauser and distributed by INTERARMS. Some of the writing on the gun (e.g., on the safety) is in German. I have shot 100 rounds through my Luger and am hooked. However, I ave noticed that on every expended case there is a horizontal indentation abot 5 m long about 5 mm below the rim of the casing. Is this normal or does the pistol need some type of adjustment? Thank you kindly, Billy

04-30-2006, 03:37 AM	#2
Dwight Gruber User Join Date: Jun 2002 Location: Portland, Oregon Posts: 3,890 Thanks: 0 Thanked 1,282 Times in 424 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