9 mm PARABELLUM ---> 9 mm PAK
I thought it is technically impossible to convert a Browning's locked breech system 9 mm Luger pistol into 9 mm PAK gaspistol.
(The basic pistol was a FEG P9R (current Hungarian police/military pistol), what was sold as Mauser 90DA in Germany for a short time.)
But is is possible, see the photos:
Finally, this is the original real pistol: