Why are some cases nickel plated?
There can be several reasons for this. If you keep cartridges on a leather belt, the tannic acid soon causes a patina to form on the brass. As a result, African cartridges often have a nickel-plated case. Many people also think that nickel-plated cases look more attractive. The friction between steel and nickel is greater than between steel and brass. It is therefore conceivable that the case is extended slightly less in the chamber.