These bullets that are basically as wide as they are long, or close to it definitely add to the challenge. There is a setting in the generator that adds a certain clearance to whatever is put in the caliber param. The default it 1.2 mm. So the 9mm plate is technically 10.2 mm. So at 8.5mm caliber you will actually be at 9.7mm. My point being there is some room to play with. You could probably set the caliber all the way down to 8mm and you will still have .2mm of clearance on that 380 bullet. Of course then the slide plate might potentially need to move out a tiny bit to compensate. Please don't take my word as gospel on what will actually work the best, because unless it is printed and tested its any ones guess.
bullet_caliber=caliber+1.2; //caliber in (mm) + 1.0 to 1.5 mm