I’ve had good experiences with the Hornady 6.5 Grendel brass since 2010. My Lapua brass comes out looking new shooting unsuppressed. I radius the edge of my ejectors and de-edge, blend and polish my extensions to make for smooth feeding. A lot of factory extensions have really sharp edges on the feed ramps.Could very well be warm, but in my Hornady experience with 6.5 Grendel, 6mm Grendel, 5.56 and 9mm, all their brass gets beat up by even light loads. I've got a 223 load, 55gr around 2600fps and it still chews up the Hornady a little while any other headstamp comes out looking new.
The tumble-polished BAT extensions have been the best I’ve seen that usually don’t require much.