Marks on the casing

[RCloud]

I went to the range the other day and fired a couple hundred rounds of factory 9mm. I noticed that the casings had scratches on them when I pick them up. What could this be from? Thanks

 

[B]

Likely from being run through a gun..... Markings are normal, the ejector, barrel and slide all contact the round during loading and ejection which can be violent processes.

 

[RCloud]

I actually laughed. Thanks. I know about typical markings, these just seemed a little heavier than normal.

 

[Garlond]

May have a sharp edge on one of the surfaces listed above. Examine the case and the feeding path together and see what could contact to make the marks.

 

[sarge]

Did you pick up some MP5 casings maybe? Pictures would help.

 

[RCloud]

Why do you ask about the MP5 casings? Whats different about them?

 

[paulz]

The chamber is fluted. MP5s use a delayed blowback system of operation. There is still some pressure in the case when extraction starts, so cases tend to stick to the chamber walls making extraction more difficult. Gas flows into the flutes and float the case away from the chamber walls so the cases don't stick and are easy to extract.

The flutes leave marks on the case and the cases tend to be dirty/smoky. Once you have seen one, you will know. Very easy to spot.

 

[RCloud]

I've seen one or two and these were factory ammo only shot through my pistol.

 

[B]

You need to give a lot more information for anyone to even guess. Pistol model? Describe the marks. A good picture would clear things up even better.

 

[stevebc]

There's even a book about this: The Matrix: 9mm Parabellum. An Empirical Study Of Type Determination", by Robert H. Kennington of the Metro-Dade Police Dep't. It's page after page of diagrams of various cartridge cases and the marks left by extractor, ejector, breechface, chamber, firing pin, etc. More info than you ever suspected could be had from a cartridge case, really.