We checked the Transport Security Administration (TSA) rules, and yes, you can, but it must be in checked baggage, not a carry-on. It must be unloaded (including removal of chambered rounds), though in most cases ammunition can be carried in the same box. You need to declare it when you check in, and you may be questioned, so you can expect some delay. We’d recommend you refer to the TSA website for current information before you fly. Bear in mind that these rules only apply to US domestic flights. Other countries have their own regulations, so you’ll need to check with the appropriate authorities. You need a permit from your destination before you travel; however, these are rarely issued to members of the general public.