There are also products made for scuba diving/snorkeling that are excellent in keeping the mask free of fog. They're inexpensive, maybe something like that would work. I've used the following Sea Gold Anti-Fog and it works well: http://www.scuba.com/scuba-gear-54/028053/McNett-Sea-Gold-Anti-Fog.html
The trick in using this gel is to apply a good layer, then quickly rinse with fresh water, and it leaves a crystal clear film that does not fog.
Also, in a pinch, I've been told that you can simply spit in your mask, rub it around and that will keep it from fogging. Divers swear by that, but I have not tried. Maybe spit on your cam & let us know how it works?
So what does your rifle cleaning kit look like? Is it a mess of bore brushes, different solvents and oils? Here may be the answer for you. I’m not going to recommend on how to clean your rifle or shotgun since you should already know that but suggest a way for you to keep all your supplies organized and where you can find them without getting four or five different boxes out to get everything together. And if you are like me and have a half dozen different calibers and...