Were we not talking about RIFLE production and not replacement or lateral support components? Actual rifle production capability and capacity is specifically related to receiver casting/forging and machining, Therein is the nature of the key and limiting tooling (molds, fixtures, gigs, and in some cases custom presses and machinery) and indeed the manufacturing processes (call it "recipe" for those with no mechanical technologies manufacturing knowledge).

Production of 1903 rifles for WWII had nothing to do with any degree of capability, let alone readiness of the previous manufacturers...which were government armories, not private sector manufacturers. SA and a number of second tier (sub-contract) suppliers continued or were ramped up to make replacement barrels and parts for '03s and A3s and even for new production as needed by SC and RA.