Hi,
Although there is a chance that the grooves will prevent the pressure build up getting critical, the 'fix' was not to protect the firing pin from breaking, but the firing pin from getting stuck due to a buildup of dirt in the cavity of the breech block. The grooves (or flutes) help to push away any dirt.
The Finnish army had an interesting 'fix' for the prevention of damage from pierced primers. They drilled a tiny hole in the bottom of the breech block, creating a channel between the firing pin cavity and the outside. Any gases could vent through that hole, reducing damage.
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