Welcome to the forum and thanks for asking our advice
Does your range allow handloaded ammunition? If not, the question is academic.
I would ask if it would be OK to load Magnum cases to Special power levels and shoot those. If not, ask if the range has any 44 Special cases they could sell you.
I believe you can buy loaded 44 Special ammunition over the internet, but buying the brass is probably the most reasonable way to go. I get all my brass from buying commercially loaded ammo and using that brass over, but that is not the only way. Buying virgin brass may be the best choice for your situation