Plating in firearms began initially as a method of corrosion-proofing in the days of black powder ammunition at least 150 years ago. Gunpowder at the time was highly corrosive, and working guns lived hard lives. Later on, plating with precious metals also became more important as decorative methods of creating more elaborately-embellished special-order guns. Nickel was the first as the electro-plating process evolved, and with a long history of tradition it's still the most popular with its ability to maintain a long-lasting wear and tarnish-resistant finish.