Error with tool changing gui?

Idea The goal of this tool is so every time the player clicks a value in the tool goes down by one, and every time it goes down, an imagelabel also changes to correlate.

Problem The only issue with this script is that it works once. the player clicks once, the gui changes to correlate and then nothing else. when you click again the value goes down but the gui remains the same. I get no errors.

Code

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

mags = tool.Mags


tool.Equipped:connect(function(mse)
    mouse = mse
    mouse.Button1Down:connect(function()
        mags.Value = mags.Value -1
    if mags.Value == 5 then
    plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393235619"
        if mags.Value == 4 then
        plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393236237"
        if mags.Value == 3 then
        plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393236950"
        if mags.Value == 2 then
        plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393237626"
        if mags.Value == 1 then
        plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393238117"
        if mags.Value == 0 then
        plr.PlayerGui.PlayerHud.Ammoi.Image = "rbxassetid://393238639"
        end
        end
        end
        end
    end
    end
    end)
end)
tool.Unequipped:connect(function()
end)

Thanks