Strike's main body done with rust weathering.. (the lazy way)
1- Very straight forward, apply gray real touch wash,
you'll get something like this. a subtle shade of oil stain.
2- Apply brown real touch marker for a hint of rust. apply as random as you can.
3- then, a lighter brown highlight.
Same goes to other parts..
Eventually, you can get something like this.. well, its not perfect. But it looks like strike is being used and rusted a little.
General update for RG Strike, now.. its time for decal