What caused this case deformation?

[rutilate]

This case was ejected from my M&P 9 and might have been the one that came back and hit my forehead rather than ejecting to the side. Might it have caught on the slide? What would cause this?

 

[saltydude]

Looks like it came in contact with another empty casing mouth by the way the two indentions are shaped. Don't know how that would happen from being ejected. Obviously took some significant force.

 

[kid_fisto]

This case was ejected from my M&P 9 and might have been the one that came back and hit my forehead rather than ejecting to the side. Might it have caught on the slide? What would cause this?

View attachment 65329

This most certainly did not happen in the chamber.

Post #2 is right that this hit something that was round, I suspect another case as well.

I say your pistol is safe to continue shooting, but I am not a gunsmith.
I do have ridiculous superfluous degrees.

 

[swampy]

Could be the next round in the magazine wasn't pushed fully to the top and the case got dinged by the magazine lips. The spacing looks about right.

 

[jpm]

It looks like it flipped over as it was being ejected (picture the dinged area on the bottom as its being fired and it does 180 degree flip end over end so the empty part of the case is now pointing back at you and almost completely ejected) and before it got fully out of the chamber, the slide caught it as it was closing and grabbed it just enough to make those marks. It didn't have enough of a 'grip' to hold it there, so the force of the slide then causes it to pivot out and over the moving forward slide slide propelling it backwards with the headstamp end flipping up abd back and then hit you in the forehead.

See if there's any kind of mark on the other end to indicate that it was grabbed this way. I don't think that happened before firing since I think the pressure would have flattened out any dings like that when it was fired.

 

[jpm]

Here's a picture of what I'm talking about but picture the headstamp end up slightly higher than the open end so it doesn't catch the slide and hold it like this one did.

 

[Ink]

Here's a picture of what I'm talking about but picture the headstamp end up slightly higher than the open end so it doesn't catch the slide and hold it like this one did.

View attachment 65344

this was my first thought as well