I have traveled to three Africa countries including SA. I always take my reloads placed in plastic holders not boxes and have never had any problems at all. They only care is it in a locked container and dies the head stamp match the caliber of your rifle. I also bought the very lightest plastic ammo lockable container I could get. I can always put 80 pieces of ammo no matter what combination of caliber still coming in under the 11.5 pound requirement. Sorry no I do not remember where I got it but I highly recommend just looking at the ammo containers and buying the lightest one as I didLeaving in August for South Africa. Carrying a 35 whelen. My question is would it be better for my reloads using Hornady brass to be put in Remington factory boxes or just a plastic ammo box?
I took my reloads in empty Federal Boxes. The ammo makers spend a lot of time and design on packaging to ensure ammo arrives at stores in tip top shape. Most factory packaging securely holds each round. The MTM plastic ammo boxes are my favorite for my handloads, but they do not protect the handloads as well as factory packaging. There is a lot of slop which allows movement and rattle.
Use the factory boxes whenever you can, and put the boxes in a lockable plastic ammo box. African (and some American) gate and TSA agents don't know what to do with reloads if they can't read a label. Save yourself grief by thinking what the dumbest person on the planet would do if they saw your box.