How to make the camera help? for lack of better title.

Well I'm making a FPS game and I ran into a problem with the Aim Down Sight feature I planned on adding to it. The camera is suppose to Move to a "Sight Block" and look forward but still act as if its in first person and then revert back to the former camera set up. I can't move the head to the sight block because its cframe is constantly being changed by a script I found that makes the head track the mouse so I welded the gun to the head and if I move the head the gun moves also. Any ideas or suggestions on how to do this would be helpful.