I know that on my Luger I could with some effort load an extra round into the magazine but a magazine with the extra round wouldn't fit with the action closed; it would fit with the action open, but wouldn't feed very well. I suspect that was just a result of a magazine with a tiny bit more space than usual, and that it wasn't designed to hold that many rounds, but the magazine would probably only had to have been 1mm or so longer to actually hold an extra round usefully in such fashion that it could be used to charge an empty weapon with one more round than normal.
supercat: I know that on my Luger I could with some effort load an extra round into the magazine but a magazine with the extra round wouldn't fit with the action closed;...
Come on, this is abuse of the mechanism, not designed use of the magazine. Exactly what I said -- this is not a gun designed as stipulated above.
With all due respect, your answer is not an answer. It would hep you to gain more respect by capitulating on this.