Выражение встречается в следующем контексте:
Again, always check with airlines, especially foreign carriers, to find out if advance notification is required. Otherwise the rules are pretty simple. Firearms must be in a lockable hard case. (Don’t forget the lock, and carry a spare) Disassembly (broken down, or bolt removed) is recommended, but be sure to check one last time to make sure the firearm is empty before you put it in the case.

Заранее спасибо