Factory cartridges or bulk load?
Factory carts have the end caps crimped on. They are quite robust. Just put them in a box and pack some newspaper around them. As long as they are not subject to heat humidity or high radiation, they'll be fine.
Bulk load carts can accidentally pop open if they get dropped or shaken hard. Make sure they are inside a plastic canister first. They pack in paper and put in a box.
I save the canisters from my factory carts to keep my bulk carts in just for safety. I've had a couple of the pop open, accidentally. It's ALWAYS at the least opportune moment!