I have 940 rnds of this stuff Factory sealed 20 rnd boxes. I have shot 6rnds in my AR and the primers come out flat; hot due to long case 'pinning' the bullet in chamber. Anyone heard of this for factory Winch. White box? It's non-magnetic labeled 223 Rem 62gr FMJ USA223R3... Edit: Standard case length 1.760 This White box 1.768 .008" longer than max case OAL ????