AR slam-fires just don't happen with proper commercial or GI loads, or properly assembled hand loads.
ace88, i applaud your willingness to actually TEST things
but note that your carrier has what is called a "shrouded firing pin" while many if not most carriers sold by companies like RRA/DPMS/etc have the rear of the firing pin exposed so that it IS possible for the hammer to hit the pin out of battery. (though that wouldn't cause an OOB incident, since the firing pin itself is not long enough to reach the primer when the bolt is OOB
Actually most if not all manufacturers use the standard unshrouded AR SA bolt carrier, some offer a FA (M-16) shrouded bolt carrier as an option or a few models have it standard (very few). No single manufacturer uses a shrouded FA M-16 bolt carrier on all models.