[whiplashomega]

As long as we are talking realism, lets talk mineral availability. Copper is actually one of the more rare minerals out there that is in heavy use. At least it is these days(I've heard some claims that in what has commonly been deemed 'the bronze age' surface copper deposits were much more plentiful than they are today, but were used up in that age). As such I would actually make the resource cost of bronze armors higher than equivalent protecting iron armors, due to the increased prospecting costs. Why did copper and bronze get used earlier than iron then? because it has a lower melting point, so before people came up with ways to make fires hotter(such as a bellows and enclosed furnaces) it was pretty impossible to separate the iron from its ore. Once these things were invented however, iron was more plentiful, cheaper to produce, and could produce a variety of useful alloys, thus the end of the bronze age. Anyway, there's my realism reasoning behind a suggestion that you actually INCREASE the resource cost of bronze armors.