On that tanneyshop site, they don't have an upper receiver that matches the one without the forward assist. Other than that are they pretty much the same? Could I just grind off that part and patch it up?
Well I'm late to the thread, but I'm currently working on this with an airsoft M-16. Since its my first time trying to make a prop, its not going to be accurate, but these links are giving me hope that I can make a good one in the future