I usually go with the Krylon for simplicity but Brownells has a spray epoxy that is pretty tuff. Yes it will yellow but not an issue on dark colors or camo. It will also sugar up or get chalky over time but by that time it is ready for a redo. Imron used to have a clear version and this was the best, not sure if it is available anymore. A clear gel coat is probably tops on wear resistance and also non yellowing but trickier to spray right, but it is worth the learning curve. These come in both polyester and epoxy with the latter being much better.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli