What should I set the Head space to for 223 in an AR? I checked several fired cases and most read 1.458 with the Hornady head space gauge. I would think that I should set my resizing die to give about 1.454. I read online that the go gauge is 1.63 and the no go is 1.73, Does this mean that my AR should be able to shoot ammo that the head space measures between those numbers? I have some that are over 1.60 and when chambered will not allow me to cycle the bolt to eject them (seem to be stuck). They may cycle the bolt when fired without a problem. This is on a Colt M4 with 5.56 barrel.