IIRC, the Lee website has updated the checklist about which primers are ok to utilize. They now appear to single out FEDERAL precisely: 223 Rem. They recommended CCI (more durable primers) for all masses Utilized in any firearm which has a free of charge floating firing pin because the AR https://210mfederalprimers68012.thezenweb.com/not-known-details-about-federal-large-pistol-primers-no-150-69879443