Duplicating a tool makes a script in it not work? Why does it do this?

I am making a game with a gun shop and the guns have a script in them that makes you hold the gun how I want them to. Yet its not an animation. But whenever I replicate it the script stops working? Can someone please help me. This is the script:

selected = false
RSH, LSH = nil, nil
GRP = nil
RW, LW = Instance.new("Weld"), Instance.new("Weld")
anim = "none"
function WaitForChild(obj, ch_n)
	local t = time()
	while not obj:FindFirstChild(ch_n) and time() - t < 10 do wait(0.1) end
	return obj:FindFirstChild(ch_n)
end
script.Parent.Equipped:connect(function()
	if script.Parent.Parent:FindFirstChild("Humanoid") then
	if selected then return end
	selected = true
	player = game.Players:playerFromCharacter(script.Parent.Parent)
	local ch = script.Parent.Parent
	WaitForChild(ch, "Torso")
	RSH = WaitForChild(ch.Torso, "Right Shoulder")
	LSH = WaitForChild(ch.Torso, "Left Shoulder")
	GRP = WaitForChild(ch["Right Arm"], "RightGrip")
	_G.Grip = GRP
	--
	RSH.Part1 = nil
	LSH.Part1 = nil
	--
	RW.Part0 = ch.Torso
	RW.C0 = CFrame.new(1.5, 0.5, 0) --* CFrame.fromEulerAnglesXYZ(1.3, 0, -0.5)
	RW.C1 = CFrame.new(0, 0.5, 0)
	RW.Part1 = ch["Right Arm"]
	RW.Parent = ch.Torso
	_G.R = RW
	--
	LW.Part0 = ch.Torso
	LW.C0 = CFrame.new(-1.5, 0.5, 0) --* CFrame.fromEulerAnglesXYZ(1.7, 0, 0.8)
	LW.C1 = CFrame.new(0, 0.5, 0)
	LW.Part1 = ch["Left Arm"]
	LW.Parent = ch.Torso
	_G.L = LW
	--
	GRP.C0 = CFrame.new(0, -1, -0.5) * CFrame.fromEulerAnglesXYZ(-1.22, -0.45, 0.22)
	for i = 0, 1, 0.05 do
		wait()
		RW.C0 = CFrame.new(1.5, 0.5, 0.25) * CFrame.fromEulerAnglesXYZ(1.3*i, 0, -0.5*i)
		LW.C0 = CFrame.new(-1.5, 0.5, 0) * CFrame.fromEulerAnglesXYZ(1.7*i, 0, 0.8*i)	
		LW.C1 = CFrame.new(0.3*i, 1+1*i, 0)
	end
	wait()
	local rg = (ch["Right Arm"]:FindFirstChild("RightGrip") or GRP)
	if rg ~= GRP then
		GRP.Parent = ch["Right Arm"]
		rg:remove()
		end
	end
end)
script.Parent.Unequipped:connect(function()
	selected = false
	local pl = player
	RW.C0 = CFrame.new(0,0,0) * CFrame.fromEulerAnglesXYZ(0,0,0)
	LW.C0 = CFrame.new(0,0,0) * CFrame.fromEulerAnglesXYZ(0,0,0)	
	LW.C1 = CFrame.new(0,0,0)
	RW.Parent = nil
	LW.Parent = nil
	RSH.Part1 = pl.Character["Right Arm"]
	LSH.Part1 = pl.Character["Left Arm"]
end)
function armReload()
	for i = 0, 1, 0.1 do
		wait()
		LW.C0 = CFrame.new(-1.5, 0.5, 0) * CFrame.fromEulerAnglesXYZ(1.3*i, 0, 0.9*i)	
		LW.C1 = CFrame.new(0.3*i, 1+1*i, 0)
	end
end
function gunOut()
	for i = 0, 0.3, 0.06 do
		wait()
		GRP.C0 = CFrame.new(0+i, -1-i, 0+(2*i)) * CFrame.fromEulerAnglesXYZ(-2.22, -0.45, 0.42)
		LW.C0 = CFrame.new(-1, 0.5, 0) * CFrame.fromEulerAnglesXYZ(4.2, 0, 2.9)	
		LW.C1 = CFrame.new(0.8*i, 1.1+i, -0.3)
	end
end
function gunReturn()
	RW.C0 = CFrame.new(1.5, 0.5, 0.25) * CFrame.fromEulerAnglesXYZ(1.3, 0, -0.5)
	LW.C0 = CFrame.new(-1.5, 0.5, 0) * CFrame.fromEulerAnglesXYZ(1.7, 0, 0.8)	
	LW.C1 = CFrame.new(0.3, 1+1, 0)
	GRP.C0 = CFrame.new(0, -1, -0.5) * CFrame.fromEulerAnglesXYZ(-1.22, -0.45, 0.22)
end