In the US (not sure about your location or the laws in other countries), the part of an AR-15 that qualifies as the "firearm" in the eyes of the law is the lowe

In the US (not sure about your location or the laws in other countries), the part of an AR-15 that qualifies as the "firearm" in the eyes of the law is the lower receiver. It's a machined block of metal and does not do anything on its own. When transporting a firearm through air travel, it's supposed to be locked such that only the owner can open it. So you can claim you're carrying a firearm with nothing but a small-ish piece of metal in your luggage. For illustration: https://i.imgur.com/ARZgZV6.png https://i.imgur.com/ARZgZV6.png. The non-transparent part is the lower receiver. As an aside, the "AR" in AR-15 stands for Armalite Rifle (after the company that originally designed it); not "assault rifle".