hi new guy! i too am behind enemy lines in wmass. nice move with the wife, mine likes guns, not shopping, and i've used up all my tricks, so any new ones are always appreciated. now to your questions. the tube itself is mount to a barrel nut, which is screwed onto the receiver threads. the tube can be removed with a strap wrench, like one to remove oil filters from cars. it may be difficult and heat can be applied if needed. the barrel nut does require a special wrench, but that doesn't need to be remove if you change the rail, so don't worry. the railed fore end should go on to the barrel nut either two ways. 1. it will "clamp" around the barrel nut, coming in two pieces the will screw together enclosing the barrel nut and have anti rotational tabs. 2. the rail you choose may have a proprietary nut, in which case you will have to remove the gas tube, take the barrel nut off, replace it all, and done. their may be other options, but these are the most common. i suggest finding the rail you want and then we can help you from there. start shopping! and get the wife involved, never know where she can help get a sale price!