Had to pull my two .40's down (P07 DUTY and P09) unload, manipulate them, field strip, manipulate them, reassemble, manipulate them and finally go grab a couple unused #2 pencils from my old box.
If the slide is back all the way to the alignment marks on the slide and frame the firing pin isn't getting hit hard enough to bump the pencil.
Let the slide forward just a bit, to where the frame alignment mark is lined up with the rear notch and it still won't contact the pencil.
Let the slide forward enough to allow the frame alignment mark to align with the rear most full width section of slide at the back of the slide and it will launch the pencil.
The hammer is hitting the bottom rear of the slide if the slide is back very much at all - but it can almost be all the way forward and the hammer will hit the firing pin and launch the pencil.
Now, is that small amount that launches that allows pencil launch enough to be the problem?
Neither the P07 or P09 allow the barrel to move downwards at the rear of the chamber/hood until the slide notch has passed rearward of the alignment marks. Even as the slide moves further rearward the barrel only drops, it does not begin to open the gap between the rear of the barrel and the breech face until the slide moves even further to the rear.
No chance of the hammer hitting the firing pin on my two pistols with the slide farther enough back to open up the gap between the slide and barrel hood.
So, what else could set off a round when the slide wasn't forward far enough to allow the hammer to strike the firing pin? Or set the round off while the slide was still moving forward?
Go ahead and dig your P07/P09 pistols out, unload them and test it on yours. Might be some out there different than mine.
Right now I'm loading mine up and nursing my sore/tender trigger finger from the way I was using the rear sight to pull/hold the slide back while trying to keep the alignment notches visible.
Ain't this stuff fun?
OP, did you pick up the rim/base of your failed brass. I got mine when it happened to me with the CZ85. When the slide came back it dropped the rim/base on the bench right in front of me. The brass case walls stayed in the chamber, like yours did.
Rim base off to the right of the next round in the magazine that I cleared when it failed to chamber. You can see how "smoked" it is from the gases that went down the frame/magazine. It clearly had an indentation in the primer. At the time everyone pretty much concluded it was a bad piece of brass. Others reported having the same thing happen to them.
A few months later while resizing 9MM brass I had the rim/base pull off and had a tough time getting the brass case walls out of the resizing die.
Might not be an OOB and might not be the poor P09's fault.
My P09 9MM is the best shooting centerfire semi auto I've ever had. It would hurt my feeling bad to have it end up like the OPs pistol. We know all pistols are not created equal (in the performance categories anyway).
