Dreaming about a gun represents anger, resentment and aggression. If you dream that you are holding the gun this shows that you feel threatened and are seeking to protect yourself from those around you that want to do you harm.
If you dream that someone else has the gun, you feel like you are being attacked and are starting to resent the person for making you feel this way.
Dreaming about a gun can represent power or impotence depending on how the gun is wielded and how the gun reacts to being used. If the gun does not work, or gets jammed, this shows a lack of power or a fear of problems with sexual performance.
To dream about concealing a gun shows that you have feelings of anger or aggression towards someone which you are trying to hide. This shows a pragmatic side to your personality and an ability to control your emotions.
To dream about shooting someone with the gun represents your negative feelings towards that person.
To dream about someone shooting you shows that you feel victimised and that there are people out to get you.
Also see Shot.