Chamber ridge
 

Would like to know if anyone has encountered Lugers which have a ridge/ring in the chamber that leaves a ring on fired brass that is about .0001 inches. Ring appears about half way down on the fired brass.

John,

Two of my Lugers also have slight ridges or rings in the chamber. I have never noticed any rings on fired brass. I would also like to know why the ring is there, but it doesn't appear to hurt anything.

I've asked this same question myself. My old DWM has a step or ridge, my Mauser does not. Somewhere I saw a cutaway picture of a 9mm luger and the chamber was stepped or slightly bottlenecked, but I can't remember where. I have the question posted in "military lugers" on the forum, but still no real answer.

Stevie.

Hello to all! This is just a WAG...but it is possible that the ring occurs when at some point in the manufacturing process, the chamber is prebored for stock removal... if done with an out of tolerance tool it could cut to deep for the finish reamer to clean it up... since it doesn't affect function...it was probably overlooked during the inspection process..."If it ain't in the plans, it ain't supposed to be there!" till...later....GT <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />

Thanks for the info. I'll let you know if I learn anything new.

Hi Rick! Thats interesting! Makes you wonder why on some, and why not on others..... Although, having it on a plan would definitly give it a purpose! Now, if we can just figure out what that purpose was!!??? till...lat...GT

Guys,

I shot both of my Lugers that have the chamber grooves today. John was right, there is a very slight ridge around the fired brass. I never noticed this because I don't reload 9 mm, I just use cheap Wallymart bulk pack ammo.

I once had a .38 Special Colt Gold Cup that had grooves all along the chamber wall to retard slide opening of this blowback design until the chamber pressure dropped. It really screwed up the finish of the cases, but it worked fine. Do you suppose there is a functional reason for the Luger chamber groove?