FWIW;

I too use hard plastic cases to ship Custom Projects to clients.
I buy them in bulk and no they don't have cardboard cases. Fed-Ex large boxes are free and by putting 2 1/2 together I have a cardboard sleeve that protects the case. Have not had any damaged as of yet in 10 years of doing this practice.

I started with Koplin hard single rife cases. Koplin has discontinued this case. Now use Doskosport. I miss the Koplin cases. They stack better and were longer in legnth

Dennis Earl Smith/Benefactor Life NRA, ACGG Professional member