I know you got a PPK I post on walter board. Natchezss.com has some 380 parts their closing out might look their I have wolff guid rod and spring set in mine. Only problem I ever had was mag release spring not strong enough. Findly had one made Its a little stiff but mag doesn't pop in my pocket any more. Look on e-bay might find barell. Have you tried cleaning barrel really good might be foulded up. Just a idea but have you checked rear sight to see if off to side or loose.
If me I would look for trigger, hammer ,sear, barrel ,slide stop,ejector and extractor. Cyl and slide I think thats their name used to do a lot of custom work on Mustangs them might have some parts. Guess I should stop buying pistols anf get some spares for mine.
One last thing If you remove grips the screws. They screw into frame not like bushing on 1911 Be careful fine thread and could be a bit of trouble if you should strip.