My HB M4 high speed tractor includes a a 160mm metal chain that is part of a block and tackle used to lift 8" or 155mm shells. My question is how to make this chain look as realistic as possible. Thought I might wet it down and let nature take its course. Any ideas would be appreciated.

I would recommend using salt water and applying heat to it. You could also try Blacken It, but it won't rust.

Thanks for that. Sounds like a plan and I will try it.