So I take the front sight post off of my AR to put a YHM Tube on, I put the gas block on and now I have the shint ring where the sight post was.. I'm concerned about rust, any suggestions on how I can cover that with something ?
Birch Casey makes a product called super blue or perma blue, these are sold at most sporting goods stores and are really good for touch ups like where the front site was. It has a chemical reaction to turn it black again.
Another voting for the "bluing"/"blackening" pens from B/C. They work very well and come in a variety of different finishes. Find the one for flat/matte black and you should be GTG.