do you shoot at a range or an area where other shooters leave their brass.....?
i have been picking up empty brass caseings since i was a lyttle kid & had to dodge dinosaurs too..!
but, i recently have picked up some shell cases, .223/5.56mm, & kinda studying them, one in particular has highly noticeable "twist" marks on the head near the rim, 180 degrees apart, wyth a slight burr that is noticeable to the touch, several other empties showed "twist marks, others did not, after filling my jacket pocket & going home & examining the indented primers wyth a 50X scope, i discovered the one wyth "twist" marks & burrs also had a badly pitted firing pin, i positively IDee'd 5 different rifles.........
my question: is/are these "twist" marks a head space problem ? or is it a possible pressure problem ?? do your AR15s show different marks on the head of fired rounds ?
do you look at them closely to know ??
if you know, does the markings differ wyth differing ammo ?