Move child to position and bring parent

Hello, my goal is to make some sort of aim down sights program that can snap onto an empty game object and shoot through it. The reason I would want this is so i can have multiple of them(multiple sights, iron, holo, ect) and swap between them fast. So my idea was to create an empty game object a little infront of my ray point. and then move the sight to that point so my gun would shoot right through it. The problem is that the sight is a child to the gun and a manager(weapons).

I've been trying to move the manager weaponsobj.transform.localPosition = camLineUpEmpty.transform.localPosition - cw.zoomCamPos[cw.currentAttachment].transform.localPosition; (weaponsPos = EmptyPoint - SightPos) but im having only partial sucsess, it only works sometimes and im really not sure what the problem could be. I have all rotations to 0, could it possibly be scale? Im not sure how to fix this and any help would be great thanks :)