John, one of my favourite containers for big NE rounds is the MTM 10 pack which I think was called the "Buff Ten".
I've used these for about 10 years or so and find they are very good.
However they will only JUST fit a COL of 4.1 which easily handles many of the NE rounds but may be just a tad too short for your loads.

Thesedays I'm a bit paranoid regarding ammo packaging for air travel as over the years I have had problems even though I had done my utmost to comply with their regulations and requirements.