Originally posted by mrbananas8:

I don't know enough about metal to know if this is exactly true for bronze, but if the smelting process effects the density then you could end up with less volume while still having the same mass.

The density changes, and volume actually increases due to thermal expansion. Only way volume would change is if some of the metal evaporated, which I do not believe is possible outside of a vacuum.

Either way, both realistically and gameplay wise, the ratio for copper/tin to bronze, and just everything around forging could be streamlined a bit better.