How do I make it so you can look up and down with a gun and the gun will follow?

wait()
Tool=script.Parent
CP,Torso,g=nil,nil,nil
necko=CFrame.new(0, 1, 0, -1, -0, -0, 0, 0, 1, 0, 1, 0)
getPos=function(Pos,TorsoPos)
	return Vector3.new(Pos.x,TorsoPos.y,Pos.z)
end
Turn=function(mouse,Torso,Gyro)
	g.cframe=CFrame.new(Torso.Position,getPos(mouse.Hit.p,Torso.Position))
	offset=(Torso.Position.y-mouse.Hit.p.y)/100
	mag=(Torso.Position-mouse.Hit.p).magnitude/80
	offset=offset/mag
	neck=Torso.Neck
	neck.C0=necko*CFrame.fromEulerAnglesXYZ(offset,0,0)
	arm=Torso:FindFirstChild("Right Shoulder")
	if arm~=nil then
		arm.C0=CFrame.new(1, 0.5, 0, 0, 0, 1, -6.48200512e-007, 1.00000274, 0, -1.00000274, -6.48200512e-007, 0)*CFrame.fromEulerAnglesXYZ(0,0,-offset)
	end
end

Equi=function(mouse)
	wait(.2)	
	CP=Tool.Parent
	Torso=CP.Torso
	g=Instance.new("BodyGyro")
	g.P=18000
	g.D=600
	g.maxTorque=Vector3.new(1/0,1/0,1/0)
	g.cframe=Torso.CFrame
	g.Parent=Torso
	while true do
		if Tool.Parent.className~="Model" then
			break
		end
		Turn(mouse,Torso,g)
		wait()
	end
	Torso.Neck.C0=necko
	g:Remove()
end
Tool.Equipped:connect(Equi)