I've read that the firing pin on an AR-15 is "floating". Therefore the firing pin has the potential to fly forward and possibly dent or ignite the primer when the bolt carrier group slams shut. Hence, the term "slam-fire". Has this ever happened to you? I'm wondering if a hardened primer, i.e. CCI #41 is the best way to go when reloading .223/5.56. Blue Skies!