Couple suggestions after traveling extensively with a sidearm.
Regardless what the rules are, be prepared to deal with a gate agent or TSA employee that doesn't know the rules. I got to where I printed off the TSA regs and those of the airline I was flying on in case I ran into someone on a power trip and demonstrably wrong in what they were demanding of me or demanding me to do.
I have the exact same pelican case as you described. One thing I do differently than many is that once I have gotten through the gate procedures (some simply make you sign the tag while I've had a few require me to show the firearm is unloaded), placed my orange tag on the outside of the case (had one agent force me to place it in the case with the firearm) I lock the case on one corner with a lock that is very snug and won't allow the case to be pried open at all. Then I use one of the many phony cable locks that come with guns and I lock the case to the inside my luggage. I pack my firearm in a bag that is a roller and I have exposed the framework of the expandable handle. I run the cable around it and then through the second hole in the corner of the case.
Your pelican case can be incredibly resistant to breaking into. But it is very transportable and very little to keep an airline or TSA employee from opening your luggage, grabbing the firearm case and taking it to work on opening later in the convenience of their home.
