This is an Alex adapter.
The old guy with two old lathes in MT, I fear is dead.
The link to his web site has been dead for many years:
But it is the softest steel I have seen to make a firing pin.
It is so soft that the firing pin in the rifle will not be damaged when it hits it.
It gets a dimple in the rear.
It is magnetic, in an Aluminium carrier.
MacFarland in his gunsmthing book does not like firing pins made from nails. He was a smart old guy, but I know I have found fault in his action vise and improved on it. Anyway, he says he likes drill rod for making firing pins. When he fixes firing pins, he Silver solders them, which I guess might leave air hardening rod still hard.
I buy a lot of drill rod from Enco, they are generally the cheapest:
I buy metal from Speddy Metals too: