Just received my 300 Blackout 15"light weight keymod 16" ar-15 upper today. Included was 3 pieces of Rem 223 cal brass in an envelope that had a card stamped "ACCEPTED" inspector MM. If they think that makes me feel all warm and fuzzy, it doesn't. I emailed their customer service asking if they wanted me to believe they shot these 223 rounds thru this 300 Blackout barrel. I know 223 cal will not chamber all the way in a 300 blackout. Guess their quality control might be questionable. Tom
