9x19 in 7,63x25 chamber

[Steinar]

Tried Alvin's experiment with the cleaning patch on the Royal I mention above. On semi auto it can't tolerate any more than just 1mm, but on automatic the hammer will release no matter how far back the bolt is. This gun is quite different internally than a C96 or M712, but I wonder if the same goes for a M712?

As seen on the picture, the top one has a small bulge on the upper part. Showed this one to Alwin earlier, he mention that it might be a softer metal than used in this one compared to the C96/M712.. makes sense to me, as it looks quite unused otherwise.

Is there any way to fix this? Or would that just make the metal more fragile in that area?