Just got a batch of once fired brass, and after tumbling I noticed these marks on the neck. What are they from, and are these cases ok to reload? Thanks in advance! My google searches turned up nada. I assume they are a form of bullet crimp?
Yep, that's just a crimp. Run em through the sizer die and reload at will. In my (somewhat limited) experience they don't affect the process or load. I have 4 reloads on Winchester brass with that same crimp in 300wsm no problems yet.