If you increase the condition high enough, then game damage never seems to effect it. This is how the special gun for the Mysterious Stranger Works.
I have seen some mods that reduce or eliminate weapon degradation, can't remember if it is for this game for the New Vegas. But, search for degradation or condtion in the Advanced Search at the Nexus. Here is one that changes the rate
http://fallout3.nexusmods.com/mods/9041
There is also one for VATS