Problem with my gun script (gui cloning)?

Well, it works fine in studio mode, but not in-game. In-game, I get the error FiringModeGui is not a valid member of Tool. And before you ask, yes FiringModeGui is inside the tool. When the tool is equipped, I want it to show the gui.

tool = script.Parent
gui = tool.FiringModeGui:Clone()
plr = game.Players.LocalPlayer

tool.Equipped:connect(function(mse)
	gui.Parent = plr.PlayerGui
end)

The script above is a part of the script that clones it. When equipped, it sends the gui into the players PlayerGui.

Try this.

tool = script.Parent
gui = tool.FiringModeGui
plr = game.Players.LocalPlayer

tool.Equipped:connect(function(mse)
	wait(1)
	gui:Clone().Parent = plr.PlayerGui
end)

I dont put clones into the locals, put it into the base script.