Barrel appears to be walking out?

[alexmg2420]

Hello, all. New to the forum here. I’m having an issue with a P08 that I purchased a while back where my barrel appears to be walking out of the barrel extension. I’m not really sure how this is possible, since Luger barrels are supposed to be threaded in and are not press fit.

First of all, yes this appears to be some kind of aftermarket barrel, as you can see by the wrong barrel profile, fixed front sight, and amazingly clean rifling (not pictured). I got the gun for absolute peanuts, so I wasn't really worried about the fact that it's a mix-master with an aftermarket barrel. Despite my googling and searching on here, I still can't figure out what kind of barrel it is, but I digress.

Anyway, I shot the gun on a couple of range trips, but eventually it stopped firing. Upon inspection, I noticed the barrel has walked out of the barrel extension somehow, causing the cartridge to sit too far forward to make contact with the firing pin. The weird thing though is that it’s walking out straight forward, it’s not rotating like a loose screw-in barrel would. Based on the lack of threads visible in the gap that is now between the barrel and extension, it looks like the barrel is a press-fit, which it obviously shouldn’t be. Additionally, on the bottom of the extension where you’d expect to find witness marks, it looks like there’s some sort of indexing pin that’s been peened in place, and it looks like there’s a matching cutout in the barrel for this pin.

So basically my question is...what on earth is going on here? I am genuinely stumped as to what kind of barrel I have and how it could possibly be walking out of the barrel extension (apparently straight forward with no rotation). Has anyone ever heard of an issue like this in the past?