That was an easy one Phil ... since it's ALL black, except the scope marking. Black requires a neutralize, it usually gets a red/magenta cast like yours did, or Blue/Cyan from lighting. In this case, since the subject and back ground are both black;
1) Duplicate the base layer
2) Convert it to black & white
3) add a mask to that layer
4) Paint the color from the bottom (original) layer back in where you want it to show through.
5) Clean up was just with the healing brush
Done.