I recently had the opportunity to evaluate this complex yet elegant piece of machinery. At the outset, this is only possible if we take a step backwards into the technicalities of cartridge brass, work hardening and the subsequent necessary annealing process.
So, to start, what is cartridge brass? It is a specific copper/zinc alloy used primarily for cartridge cases because of its superior cold-forming characteristics. At a zinc content up to marginally above 30%, the alloy formed is termed a single-phase copper alloy or α-Cu cartridge brass, and the zinc at these levels is fully soluble in the copper. Above this value, an α-β two-phase brass, which is less malleable, results. Cold-forming or working brass changes the microstructure, which increases hardness and decreases malleability, thus making the case pr to…
