Definitely looks like a feeding dent to me.
Often, cases that smack the chamber edge look just like that case.
The type of rifle will tell you if it's likely. DBM type actions seem to have problems in this area than integral box magazines do.
It could be the feed lips directing the shell into the top of the feed ramp, which sends the shell into the top of the chamber edge.
A good GS will be able to diagnose and fix the issue.
Get him to cycle a few slow, then some fast to see if he can determine when/how it's occurring.
Cheers.
gun)
