Steel and aluminum cases can be reloaded quite successfully. After all, the original factory loaded them just like they load brass cases. All the principles are the same
BUT it takes a different set of dies because of the 'spring back' for each material. When you form brass, you form it slightly smaller and it springs back a little when you pull it from the forming die. So you make the die to a specific undersize and the brass springs back to the intended finished dimension.
Same with steel, aluminum, magnesium, and all other metals. But they spring back to different dimensions. The dies we buy for reloading are specifically brass dies, not steel or aluminum.
Unless you have custom dies made in the right dimension, it isn't reasonable to try to reload steel or aluminum.
Also, many steel and aluminum cases are berdan primed.