I found this cartridge in July of 2011 on the shore-line of the Neva river just up-stream from Otradnoye outside of St. Petersburg. My Russian in-law father says it's German. The cartridge had deformation on the far-side, - which leads me to believe it was the cause of a gun jam. Even my in-laws now use the German concrete bunker as a storage shed. Any ideas as to whether it's Russian or German? And what gun could have it come from. Not that I'm married to it, - just kind of wondering if it's worth any money here in the states. My son and I found alot more catridge casings with either a F-103 marking or a P-?o3 marking, - sometimes copper (or steel) based on that it's eithe red or green corrosion. They appear to be a dime-a-dozen. -Thanks, *** Edit: I've included a pic of the what I call the 'bunker'. It's the cement portion of the shed. *** Edit2: I just noticed that there's actually a step in diameter at just below the 12 in mark on the ruler. I've looked for pics on the internet, - none have this kind of step.