How can i give gun change animation on gun change script?

Questions & Answers
1

I want to give animation to FPS between gun changes.

2

Well, the question is not quite complete, could use some more detail, but basically you just need to call an animation for the player using animation.CrossFade or something else that suits your needs. You could write a script that has a bool variable that is true when the player changes the gun and while it’s true play the animation, something like this:

if(change_gun)
{
animation.CrossFade("change_guns"); //this animation should be present in your character's animation
}

Take a look at this reference http://unity3d.com/support/documentation/ScriptReference/Animation.html