I have a .40 cal. Gen 2 model 22 Glock and have recently noticed the inside of the slide is becoming worn on both sides, at the ejection port. I’ve owned the pistol for many years and this is a recent occurrence. I see no other worn areas that match on the frame. It appears as if something has struck so hard as to gouge the metal. I recently shot about 100 rounds of Blazer 180 gr. FMJ ammo. I have used that ammo many times in the past without a problem. Anyone have a clue?