I use Delta whenever I can ..United sucks..and have caused me more problems than all other airlines
combined...

As to gun cases and ammo..all airlines want them to be locked..buy/use TSA approved locks..that way once your guns are checked..when TSA opens the case you won't have to hand them the keys to the locks as there is a side key hole all TSA keys will fit to open..saves you that hassle.

I also always lock my ammo box as well and most require you to do so anyway..

Keep you expensive optics as in bino's in your carry on..I never leave my bino's anywhere other than with me..

For convenience and making the long flight more enjoyable, I picked up a set of Bose noise cancellation headphones..they sound way better than what the airlines give you and cancel a ton of the noise of the plane and people around you..make sleeping really nice as you will be in the plane from Atlanta to Jo-burg for 16 hours..give or take..

The last time I went through Jo-burg I hired a service to get me through with the guns and all..I arrived with about 8 others -handed my paperwork to the representive..was the first one out of there..was about $150 at the time ..well worth it IMHO...