I have not flown with guns internationally in recent years but the rule used to be that you use your own padlock after TSA inspection at the departure airport. Ignorant United employees once delayed a 747 from SFO to London for over an hour, generally treating me like a criminal while demanding nonexistent permits and insisting that the case should be unlocked, not even bothering to check their own regs. TSA eventually set them straight.
I have used Pelicans to carry delicate dart guns for over 20 years in Africa. They rattle around in the back of the pickup in very dusty conditions, often with dead cows, Hilift jacks, spare tires, or Masai warriors sitting on them - never a problem.
