Metal to metals not so bad aslong as it's well lubricated and not some random Pot metal.
I think what I've currently got bar the pest controls should be alright but .177 isn't so bad to get a good amount of so a different tins no problem and can be factored into the budget (which I still need to figure out), don't think I'll have much luck in a local rags though as they stopped printing the ones round here.