What's going on here? With pictures

[xraysur]

As a relatively new handloader, I am always trying to learn new stuff. I've picked up some 9x19mm cases that look unusual and I am hoping that someone can tell me what causes them to look so strange. These ARE NOT ANYTHING I LOADED; I just picked them up along with other brass on the ground – probably at a local IDPA match. From this, I hope to learn what NOT to do. Notice that the mouth of the cases are compressed for about 0.100” and then the case flairs out. If you are having trouble seeing what I am talking about, look at the last photo below. I think it may show the problem the best.

You can see that there are a mixture of headstamps. I believe that I've found these strangely shaped cases on more than one occasion. The cases in the second photo are in the same order, left to right, as the first picture – they are just lying down.

Here are a couple more photos including a digital caliper to show the outside diameter of the case mouth and the largest outside diameter of the case.

Are these the result of some sort of extreme crimping process? Did they see really high pressure? Were the shot in a gun with a weirdly shaped chamber?

Are there any reasons why I shouldn't reload these cases to minor power factor? When I run them through the resizing die, they come out looking pretty much the same as any other case.

[falconpilot]

^{You picked up my brass!!}

^{High pressure Open gun loads, and maybe some shot through a glock ..}

[Chris iliff]

Reload them, following normal reloading procedures.

On gun ranges you are gonna pick up all kinds of brass shot through all kinds of chambers. Tight chambers, loose chambers and everything in between. All the head stamps you show are good as far as I know. There are some 9 makers that I avoid, like A-Merc.

I would think most of your questions could be answered with a yes, but it really doesn't matter. Treat the brass like all the rest you reload, following all proper procedure.

[56hawk]

Those were shot out of a 9mm with a stepped chamber. The original P08 Luger chamber was cut like this:

[jcc7x7]

56hawk interesting!!

[Blankenhole]

That is very interesting. What was the purpose of a stepped chamber?

[Slidestop]

Wow! Live and learn. Iv'e never seen anything like those.

What is the dashed ring about half way down the case?

[RDA]

Wow! Live and learn. Iv'e never seen anything like those.

What is the dashed ring about half way down the case?

You have never seen 9mm cases with that ring (referred to as the cannelure)? I see it a lot in Federal, Aguila and Remington (and probably others), it is there to prevent bullet setback.

[EngineerEli]

My HK P30L made those marks, and you could see the step if you looked into the chamber with a flash light.

I believe the idea was that the smaller diameter at the end of the case enabled a better seal between the case and the chamber during combustion. After the bullet leaves the barrel, the slide starts recoiling, and the case makes it past that short step there is much less resistance between the case and the chamber walls which aids in reliable extraction.

[rtp]

What Eli said - supposed to be for a better seal.

Newer Walthers also have a stepped chamber, or at least my PPQ does.