OK so bear with me, Im a new reloader, and new to shooting, and loading rifle rounds. So I had my first range trip out with my new to me 336, and my pack of 170gr Winchesters, and fired off some rounds. I do plan on reloading, so I saved the brass. Well looking over the brass I see all of them have a ring at the base. You cant really feel a bulge or anything... just mostly looks different. Is this something that's normal? Should I worry?? Thanks for any info!