Please Help - Anyone Know Why This AT-TE Gun Script Isn't Working?

The goal is basically to draw a ray, and put an explosion at the end of it. This is my script that I somehow botched.

local ATTE = game.Workspace["AT-TE"]
local tool = script.Parent
local user

tool.Equipped:connect(function (m)
    user = tool.Parent
    m.Button1Down:connect(function ()
            local ray = Ray.new(ATTE.Cannon.Cannon.Cannon.CFrame.p, (m.Hit.p - ATTE.Cannon.Cannon.Cannon.CFrame.p).unit*300)
            local hit, position = game.Workspace:FindPartOnRay(ray, user)

            local distance = (position - ATTE.Cannon.Cannon.Cannon.CFrame.p).magnitude
            local rayPart = Instance.new("Part", user)
            rayPart.Name          = "RayPart"
            rayPart.BrickColor    = BrickColor.new("Bright blue")
            rayPart.Transparency  = 0.5
            rayPart.Anchored      = true
            rayPart.CanCollide    = false
            rayPart.TopSurface    = Enum.SurfaceType.Smooth
            rayPart.BottomSurface = Enum.SurfaceType.Smooth
            rayPart.formFactor    = Enum.FormFactor.Custom
            rayPart.Size          = Vector3.new(0.2, 0.2, distance)
            rayPart.CFrame        = CFrame.new(position, ATTE.Cannon.Cannon.Cannon) * CFrame.new(0, 0, -distance/2)
            game.Debris:AddItem(rayPart, 0.1)
    end)
end)

Anyone see where I faltered? Thanks in advance.