This is why you fully inspect your new rifle...

[browningautorifle]

When we welded something like that firing pin body we sharpened it like a pencil in the lathe. Then you build it up. You can't weld two ends together without filling it. Cutting the groove gives you edges to weld to. Then you carefully take it down. I had to do a '73 Winchester firing pin once...HAD to as there were no replacements.