I've used Winchester primers and Winchester brass in .223 in the past with perfect success in full power 62 and 69 grain loads used in AR-15 rifles fired in law enforcement advanced weapons training when I was involved in that sort of thing. I've got 7,000 of them and if I had an AR, or any .223/5.56 rifle to use them in, I would do so with no concern over suitability or reliability in the AR platform.
JP