Well, here are come characteristics of brass that seem to make it more amenable to cottage industry, less likely to spark and ignite gunpowder. looks like gold...etc that mak be part of the explanation of why gunsmiths seemed to prefer brass for gun decor..........
Brass
Composition Brass is any alloy of copper and zinc.
Properties Higher malleability than zinc or copper. Low melting point (900 c); flows when melted. Combinations of iron, aluminum, silicon & manganese make brass corrosion resistant. Susceptible to stress cracking when exposed to ammonia. Not as hard as steel.
Uses Decorative; Low-friction applications (locks, gears, doorknobs, ammunition, valves); Plumbing/electronics; Musical instruments for acoustic properties; Zippers & uses where it's important to negate spark(fittings & tools around explosive gas).
Color Muted yellow, somewhat similar to gold, but duller.
History Brass was first known to exist in about 500 BC