Problems rotating turret with hinges

Help and Feedback Scripting Support
#1

Hello everyone, I have a turret script, that for some reason glitches really bad.
Here’s what I mean:
https://gyazo.com/837fe11fc10fed992607e23420c9b210

The turret:
image

Script:

local rpart = workspace.TurretTest.RPart
local rpart2 = workspace.TurretTest.RPart2
local seat = workspace.TurretTest.VehicleSeat
local plr = game.Players.LocalPlayer
local mouse = plr:GetMouse()


local UNIT_X = Vector3.new(1, 0, 0)
local UNIT_Y = Vector3.new(0, 1, 0)
local UNIT_Z = Vector3.new(0, 0, 1)
local IDENTITYCF = CFrame.new()

local function lookAt(eye, target, normalId)
	local cf = IDENTITYCF
	local forward = target - eye
	
	if (forward:Dot(forward) == 0) then
		return IDENTITYCF + eye
	end
	
	if (normalId and normalId ~= Enum.NormalId.Front) then
		local face = Vector3.FromNormalId(normalId)
		local axis = math.abs(face.z) >= 1 and UNIT_Y or UNIT_Z:Cross(face)
		local theta = math.acos(-face.z)
		cf = CFrame.fromAxisAngle(axis, theta)
	end
	
	forward = forward.Unit
	if (math.abs(forward.y) >= 0.9999) then
		return CFrame.fromMatrix(eye, -math.sign(forward.y) * UNIT_Z, UNIT_X) * cf
	else
		local right = forward:Cross(UNIT_Y).Unit
		local up = right:Cross(forward).Unit
		return CFrame.fromMatrix(eye, right, up) * cf
	end
end


while wait() and seat.Occupant ~= nil do
	local pos = mouse.Hit.Position
	rpart.CFrame = lookAt(rpart.Position, pos)
	rpart2.CFrame = lookAt(rpart2.Position, pos)
end