Custom gun mesh and FPS template

Alright, so I made a small mesh of a gun in Blender but added no bones because I want no animations or anything right now. I added it into the game and I was wondering how to make it take the place of the blue gun on the FPS template arms?

What you are trying to do is incredibly simple and only takes a little research on your part.

Here is a decent video I just found near the end has some instruction on how to implement your own custom weapon.

Thank you so much!