wheellock mechanism requires a good steel! parts exposed to high loads are tool steel (1% - 1.5% carbon). . must skillfully tempered steel .when use inferior steel, it is necessary to enrich the carbon steel. It also screws carbon steel, when the screw has a soft steel, it is necessary to enrich the carbon steel..
wheellock mechanism requires from the builder good knowledge of the mechanical properties of steel , and requires from the builder, the skill enrichment steel using carbon.
good mechanism wheellock = a lot of work + workshop experience ( technology, engineering, humility...)