That's a one fancy piece of kit Buckstix - & as rare as rocking horse poo by what kuduae's says!
If no luck getting cases you might be able to try Bruce Bertram here in Oz & see if he could make a run of them if you provide the dimensions.
Found his contact details for you mate
https://www.austandnzdefence.com/listings/listing_details/bertram-bullet-co-pty-ltd