Brfore you go rebarreling have you tried the Finnisn 7,65 mm ammo from Samco Global Arms. I have not had any trouble with it. But if you do decide to rebarrel to 9 mm I would be interested in purchasing your 7,65 mm barrel if it is 120 mm long and has an unpitted bore.
The Wizard
PS I have some of the Finnish ammo. Might work something out to get you some.
Samco Global