Firing pins have been made from a wide variety of materials for a wide variety of applications. The Bullet Proof® Firing Pins claim to fame is that it outlasts all other 1911 firing pins, bar none. When you're after shear reliability that's the most important quality a firing pin could have.
Made to the upper end of tip diameter specifications (.0685" to .0695") to improve ignition and prevent primer flow from high pressure cartridges.
May require light polishing to fit some slides.