I used an SKB 2 rifle case to take a .500 double and a bolt .375 overseas. It came with TSA locks but I got two lengths of heavy chain and two pad locks and put a locked chain tightly around each end of the outside of the case. Then I got some duct tape and taped the chain to the case so it wouldn't rattle or catch on things. It worked extremely well during it's journey of 8 different plane rides - 4 each way......

Now I've moved to a pelican for my next overseas jaunt but haven't had opportunity to try it on any long journeys yet.

The SKB case is what I currently use to haul expensive guns back and forth to the range in the back of the pickup. I'm none too gentle and am not above throwing the case roughly over the tailgate and my beautiful rifles don't feel a thing!!