Originally Posted by
patrick sweeney
OK, the reason why HK made the firing pin that shape it is? First, let's back up a step.
Having decided to make a "better" AR, the full Germanic engineering mindset kicks in.
Even doing something as simple as making their own AR upper, they (in all likelihood) considered every surface, every angle, every radius, and every alloy, heat-treatment and surface finish. I would not be the least bit surprised to find honest-to-god computer mainframe time devoted to cycling simulations.
In the end, they made a rifle that was heavier, with stronger springs, and the extra feeding/chambering forces required a firing pin lock to control slam-fire possibilities. "Is there a chance of one slam-fire in ten million chambered rounds? Yes, then we put in a firing pin safety."
They made the firing pin the shape it is, for what seemed to to them to be good engineering reasons. Can we ever know those reasons? Nope. Unless you find the HK engineer involved, shoot him up with truth serum, and threaten to key his beemer if he doesn't talk, we won't know. And even then, he'll probably give a decoy answer.
It is what it is, accept it and move on.