It doesn't look like it's been used, but like has been said, used to lock castle nuts. Were those used on wagon hubs or artillery hubs? I don't think so, although to say never would be wrong, because somewhere, someplace it's certainly possible. On the wood hubs with wooden spokes that I'm familiar they weren't used. It's very common on farm machinery over the years, where they are used to keep nuts from working loose, or pins from vibrating out. I'd say it's very doubtful that your find comes off a cannon.