The problem with MOST blank firing guns is that the "outer" barrel is made of zinc instead of steel. This zinc material is not as hard as steel and therefore, it is not blued, its black surface gets scratched really fast. So I can tell you, on a WALTHER blank firing gun this is normal. Especially with the PK 380 because this model has a steel slide that is in fact more durable than a zinc slide - and the outer zinc barrel. This does not lead to functional problems - it just looks pretty awful when you take off the slide.
The safety on the PK is a pretty good one, it combines a safty catch with a "flying" firing pin and a safety block that keeps the hammer off the firing pin. Firing this pistol in SAFE mode is nearly impossible. Maybe you had the safety lever in the upper position? Because this is the FIRE position. SAFE is the lower position. ;^) Or easily - if the safety lever points to the muzzle / barrel - it is ready to go BOOM, if it points to the trigger, it is locked.
Motorbiker, you're the best! Thanks... Yep, looks too scratched and feels like it was used for ages. And this is just for a day
Maybe I will try to paint is, like Robert told me to do...
About the safety, my fault... Works like a charm Thank you all! Great forum...