I was recently shooting a Stainless Steel Kahr K9 9mm. After examining the extracted cases (ammo used was winchester factory ammo), I noticed that the cases looked strange. They appeared to have a "stair stepping" like pattern/indention on the outside of all of the extracted shell casings from the rim of the case down to about halfway down the extracted case. The extracted cases looked like they had either been compressed and bent on one side or that they had been caught up on something while trying to eject or feed the round. All of the rounds fed into the gun fed and extracted properly. I was just wondering if this was something typical of Kahr's firearms or if this was a feed / timing problem of the K9? Is this what a ballistic fingerprint is, or is it some other type of problem w/ the gun? thanks.