A friend of mine, who's a public relations guy in the firearms industry, had a carry-on duffle bag with a stiff plastic plate in the bottom. We made a trip to New Zealand together in 2007, flying of out of LAX, and when we returned the TSA people found a fired .30-30 case under the plastic plate. The interesting thing was that he hadn't taken a .30-30 to NZ, and in fact hadn't traveled with a .30-30 in around 2-3 years--and the LAX TSA folks hadn't found it when we checked in to fly over to NZ. (Luckily, he didn't have much trouble.)
One of the airports I've had some trouble with is Minneapolis-St. Paul International. On two consecutive trips to somewhere further east I was called down to the TSA office because my GUN CASE showed traces of fired smokeless powder during their tests. I had to go down in the underground baggage area to open the case and so they could--what? Make sure the case had fired guns inside? They admitted everything was legal, but didn't apologize--even though in the second instance I missed my scheduled flight to Montana.
