Depending on the twist rate of the bbl. may not like the 135 grain pill. My understanding from a lot of shooters the 1:32 twist is the ideal bbl for the 115 JHP bullets, if you can get the bbl for your gun. Might want to try 147 grain and 124 grain boolits too. You "Possibly" have a 1:15 twist 8 groove bbl that would more than likely like the heavier boolit. This being a copy of the Beretta and designed as a service type gun is not a competition gun unless some modifications done. KKM use to make a 1:32 twist bbl. for the Beretta 92(should work), but availability is hard. Quite a bit of custom work by David Sams of the AMU turned the Berettas into high quality competiton guns for the army. Depending on what you are looking for and how much time and money you want to invest, and how hard it is to obtain guns your neck of the woods, might consider a 1911 style pistol.
Try some heavier weight boolits to begin with.
Try some jacketed or plated boolits too. Experiment.
Do you handload or get store bought ammo?
Hope this helps a little.