Got some case head ejector swipe in my Aero 6.5 Creedmoor using a 123 Hornady match bullet and moderate loading of AA2700, and am going to try a slower powder such as W748 and Vihtavori N140. After doing much study of what's going on with ejector swipe in AR-10 with moderate loads, this article explains it the best.

https://www.shootingillustrate...ent/case-head-swipe/

Adjustable gas block will fix it. Most large frame AR’s are overgassed all to hell.