i have two AR10 platform rifles in two different cartridges that I noticed are making ejector marks on the cases. The only common factor I can see is the barrels were made by the same company. The ejector marks are occurring using factory loads, and several different brands and bullet weights are doing it. I have read a few threads saying ejector marks are a sign of excess pressure, but that doesn’t seem likely to be the issue for factory loads. Also I have done a lot of chrono work and my factory ammo is always within 50 fps or so of what they say on the box, usually slower because my barrels are shorter than their test barrels, so I know the rifles aren’t shooting at higher than normal velocity. I’m wondering if it could be related to the new case shoulders being a little short for the chambers so the case heads are getting slammed back against the bolt face with a little momentum when they ignite. I’m very interested to hear what others think. Also, any thoughts on whether cases with ejector marks can be safely reused?