As Jericho says, used in talking about wheels (not just rims !), talking about many items beside just various weapons.
And no, the term "alloy" does not mean or have any strict connection to aluminum, odd spelling or not.
Similar to people misspeaking when talking about "clips" vs. "magazines" (these are different items), "rims" vs. "wheels" (these are different items), (cars/trucks), I could go on..!
Thanks all for your reply's.
Mike