Patrice, does this example have
both a relief hole in the breech block
and a relieved firing pin? I'm leaning toward pressure relief as the inspiration for the firing pin cuts, and see the relieved bolt as another option for doing the job. That would make longer operation without thorough cleaning an bonus--a not-necessarily-intended side-effect...
if the pictured example is representative and does not have a relieved firing pin. If it properly has both, then the scale tips toward tolerance of debris!
Since reference material recording such a change is missing--presumably forever--then we will never have a definitive answer.
