What manufacturer? S&W PPK's have some well known sight issues, and the contractor that warranties them may have some answers. Lighter loads may help too. Defensive ammo often shoots higher, as does gimick ammo like that plastic matrix crap, or safety slugs. A much easier option would be lowering the rear sight to line things up if it shoots high with normal ammo. A typical handgun is 0'ed at 10-25 yards. so if your shooting closer, it will be hitting higher if the sights are right.