Do you ever get the feeling that no matter what or where, TSA just does what it wants and it is never the same in different places. There is no set pattern to their ideas.
Two years ago in Dulles upon returning from South Africa, I was asked by a US Customs agent if I had a 57 for my firearms, I said I didn't, he wanted to know how I got my firearms to Africa, I said I put them on an airplane. This went on, back and forth till I opened my folder and showed him the 4457s for the rifles and his reply was that's what he meant. My response was they are 4457s, didn't get anywhere with him. Lord help us.
Last year the US Customs agent in NYC couldn't believe that I went to Namibia and wasn't bring anything home with me. He didn't seem to believe that, I only had my clothes and firearms with me. In NYC, TSA tried to open my ammo box in my luggage but didn't cut the lock or get the lock open but then they never closed the case back up either. Go Figure.