I have read and asked about this a lot. I never get a concrete answer on this. What are the scallopped shaped marks under the slide on the area that scoops up the cartridges from the magazine ? I have heard that they scrape the cartridges rearward to keeps them properly seated in the magazine until ready to be fed into the chamber . Is this correct or is there a different purpose ? I ask because I have different guns and none have these marks in the same area. All mine are slick and machined very fine. Any help is appreciated.