An FYI - Most airlines limit you to 10kg (12.2#) of ammunition. Must be in original boxes, or ammunition boxes. Ammunition and mags (unloaded) do not need to be in a secure (locked) container.
Make sure you have your cell phone number on the card you fill out at the airline checkin counter so TSA can contact you if necessary. Some airlines will have you open your suitcase at the check-in counter to inspect the case, and locks, and sometimes weigh the ammunition. Have them tape the card to the outside of the firearms case. Do not let them put it inside the firearms case. If TSA needs to get into the case (remote inspection), and the card is not on the outside of the firearms case, they will cut the locks to get to it.
Most airports I’ve travelled thru, the airline check-in person will give you the card, and send you to a special TSA check-in point for inspection. I always take a couple zip ties with me. When the TSA Agent is finished swabbing your firearms container, and inspecting your suitcase, if you ask them they will put them on your suitcase where those useless suitcase locks go. Gives you a real quick indication if your suitcase has been tampered with when you go to claim it at your destination.
Do not put suitcase locks on your suitcase. They will be cut off.
Pack your firearms suitcase with clothes you don’t mind having wrinkled or not re-folded back up. Some of the TSA folks root thru the suitcase like a hound going after a rabbit down a hole.
Put the gun case “nested” on top with other packed items around it so little else needs to be removed to take the case out.
At some airports, the airlines put the suitcase on the conveyor with with the rest of your luggage. Most of the ones I’ve travelled thru you have to take your suitcase seperately to a TSA inspection point. Have your firearms case keys handy when they inspect in case you need to open the case. Of the 20, or so, times I’ve had mine inspected in my presence, I’ve only had to open the gun case once.