Help with ejector marks and over-pressure

[Lemonaid]

Short version is there are two main things that will cause ejector swipe and extractor swipe in a gas gun. One is over pressure in the chamber, the other is due to execess gas going through the system causing the bolt to unlock and extraction to start not at a optimal time. (At least that's what I was told). So if velocity from your load is at a safe level according to trusted load data, it's likely a gas adjustment problem.