Which factory ammo did you shoot? It seems that Blazer and now Federal Eagle are a bit softer than regular 9 Luger. I have read somewhere that 9 Para of the time was not as hot as modern ammo and that it mattered with the P08.
P08 pistols need to be loaded with enough powder to create enough pressure to achieve somewhere between 1200 and 1350 fps.
There are a couple of things that could have caused your issue, such as an unnoticeable hangfire or weak spings etc.
The toggle system works very well, unti it doesn't.
Unless it's +P, most standard commercial 9x19 is well within the specs of your pistol
The later P38 doesn't like low velocity ammo much either, unless the springs have bee modified to handle it.
I believe the issue with ammo came from the several types issued during WWII that were intended for submachine guns.
Back in the early seventies, I loaded some steel case/black tip, German issue 9x19 into a P38. On the first shot, the extractor/plunger/spring assembly was ripped off and so was the top strap on the slide. The firing pin tip was broken as well.
Luckily those parts were readily available back then.
An acquaintance loudly proclaimed that his immaculate Inglis, P35 Hi Power would digest that ammo no problem.
Without asking, he grabbed a handfull out of the issue box and filled his mag.
First shot, OOOPPS. There was a flash flame out of the ejection port, the extractor/plunger/spring disappeared and his slide was stuck half way open, on a bulged barrel.
The ammo you used may have been on the hot side and if it used the Blazer Aluminum case, may not have been strong enough.
Sad that happened, but at least the part is available from a few sources. Likely not cheap though.
