The following article is copied directly from the Transportation Security Administration website, and can be referenced here
You may transport unloaded firearms in a locked hard-sided container as checked baggage only. Declare the firearm and/or ammunition to the airline when checking your bag at the ticket counter. The container must completely secure the firearm from being accessed. Locked cases that can be easily opened are not permitted. Be aware that the container the firearm was in when purchased may not adequately secure the firearm when it is transported in checked baggage.
Contact the TSA Contact Center with questions you have regarding TSA firearm regulations and for clarification on what you may or may not transport in your carry-on or checked baggage.
- When traveling, comply with the laws concerning possession of firearms as they vary by local, state and international governments.
- If you are traveling internationally with a firearm in checked baggage, please check the U.S. Customs and Border Protection website for information and requirements prior to travel.
- Declare each firearm each time you present it for transport as checked baggage. Ask your airline about limitations or fees that may apply.
- Firearms must be unloaded and locked in a hard-sided container and transported as checked baggage only. As defined by 49 CFR 1540.5 a loaded firearm has a live round of ammunition, or any component thereof, in the chamber or cylinder or in a magazine inserted in the firearm. Only the passenger should retain the key or combination to the lock unless TSA personnel request the key to open the firearm container to ensure compliance with TSA regulations. You may use any brand or type of lock to secure your firearm case, including TSA-recognized locks.
- Firearm parts, including magazines, clips, bolts and firing pins, are prohibited in carry-on baggage, but may be transported in checked baggage.
- Replica firearms, including firearm replicas that are toys, may be transported in checked baggage only.
- Rifle scopes are permitted in carry-on and checked baggage.
United States Code, Title 18, Part 1, Chapter 44, firearm definitions includes: any weapon (including a starter gun) which will, or is designed to, or may readily be converted to expel a projectile by the action of an explosive; the frame or receiver of any such weapon; any firearm muffler or firearm silencer; and any destructive device. As defined by 49 CFR 1540.5 a loaded firearm has a live round of ammunition, or any component thereof, in the chamber or cylinder or in a magazine inserted in the firearm.
- Ammunition is prohibited in carry-on baggage, but may be transported in checked baggage.
- Firearm magazines and ammunition clips, whether loaded or empty, must be securely boxed. Read the requirements governing the transport of ammunition in checked baggage as defined by 49 CFR 175.10 (8).
- Small arms ammunition (up to .75 caliber and shotgun shells of any gauge) must be packaged in a fiber (such as cardboard), wood, plastic, or metal box specifically designed to carry ammunition and declared to your airline.
- Ammunition may be transported in the same hard-sided, locked case as a firearm if it has been packed as described above. You cannot use firearm magazines or clips for packing ammunition unless they completely enclose the ammunition. Firearm magazines and ammunition clips, whether loaded or empty, must be boxed or included within a hard-sided, locked case.
- Please check with your airline for quantity limits for ammunition.