So you're saying the ones on the right were shot and not touched after they were ejected and the one on the left went through your RCBS full length resizing process and still came out looking like that? Normally the first thing to look at when you resize and have a dented casing is that you're using too much lube or you haven't got your die set up in the press properly. I'll defer to the expert reloaders on here because I don't reload that much stuff to offer anything else. Was any of that ammunition from the factory or all of it reloads or what? It appears the rifle needs to be thoroughly examined by a competent gunsmith who can check the chamber, etc. Are those .223 or 5.56rounds by chance, as if they are the latter that could be your problem from what I've read on those very similar rounds but that they shouldn't be interchanged due to pressure variations?