It is quite marvelous that iron and steel were "discovered" or developed in many parts of the world, almost at the same time (give or take a couple hundred years). The fact that carbonizing iron and quenching it from high temps, in order to harden it is also an almost universal phenomena. Why carbon? and how do you get it to mix? We live in a world of information, but a quick search on this web site will illustrate how baffleing it is to harden a frizzen. Not that it's difficult or that we are too dumb to get it, it's just out there, slightly beyond our understanding. The ancients did have steel but they had to make it from iron in smallish pieces so the carbon would migrate deeply. Many many northern European swords have been excavated that were made of iron and a few laminated steel swords have been found. Blister steel was made by pack hardening wrought iron bars for a period of days, that length of time is what is responsible for the blisters. The standard for size bars to be blistered was about 3/4" by five inches which is just a little bigger than the typical British anvil face, hmm. A North American gunsmith/ blacksmith could pretty easily make a gunlock spring out of iron and carburizing it in the shop, but just as we can say today "why make a lock when you can just buy it? the old smith might say " we can simply buy finger steel, so why make it here? Not every question needs an answer but all questions need to be considered.Clint