I picked up some .308 nickel cases in a batch of stuff I bought. I don't have a .308 so I gave them away. I guy I gave them to commented that they felt hard when he sized them and they do not want to chamber in his rifle. Is there a way to condition them or are they just junk? I have read you can't anneal nickel because the heat actually hardens it and makes it brittle. Any advice is appreciated.