Luger ID .30 cal or 9mm

[Josafoot]

Hello
First luger and all.

From the original owners information: 1916 DWM 9MM P08 luger.

When I was trying snap caps at the store, they would not chamber properly. The action would mostly close; however, there is a 1/8" gap where the action meets the barrel. The arm had almost fully depressed but was not quite there. I did not get a picture of the misfeed.

I am concerned that this is not a 9mm luger. I compared the markings as best I could to the given year and it is possible that it could be either a 9mm or .30 cal.

There is a picture of what the arm looked like when the misfeed happened. It does that once in a while when working the action with no magazine.