Since the "newer" medical type camo tapes don't actually adhere to the gun w/ adhesive, but to the tape, which is why you do a spiral overlay w/ the tape and a final wrap at the end which is tape-on-tape, you can apply a good rust preventative to the metal parts of the gun and not overtly impact the tapes holding ability. However, I would be cautious if the gun got wet, since the tape will trap moisture under it. I sell this type tape for medical applications and it is designed to "breathe" on the skin, but the skin is also generating heat which evaporates moisture. I've got two shotguns w/ the Beartooth Comb Raising pads on them and use the stretch camo tape on the rear of the pads to the recoil pad to eliminate gaps and make a smooth seal and have had the same tape on one gun for 3 years. But then, it's not metal.
