Quoted:
That would probably work, but for I would have to add and extended tube. That would be fine, but it would place the light pretty far out. The forearm covers almost the entire mag tube, precluding mounting anything within reasonable grasping distance. I know I'm being real anal about it, but I just don't want to hang anything off of it that takes away from the sleekness of the design.
I have an extension on my shotgun and the light and mount is almost flush with the base end of the extension (just a little beyond where my hand rests). You can put the light at 9, 6, or 3 o'clock. Don't forget that most tac-lights can use a pressure switch, eliminating the need to reach out and click the light on.
Remember, its not a fashion show. Looks shouldn't outweigh functionality of the weapon. If a light makes the gun look "ugly" to you then that's fine, but it will be a bitch trying to kill the thug that wants to kill you and/or your loved ones in the middle of the night when you cant see anything.
If you want that gun to stay sleek looking, then don't do anything to it. Invest another $400 on a 870 or mossy equal, flashlight, mount, and extension.