It is possible to print magazines and then use the print out in lost wax casting, though that does take more equipment and time. With a larger investment in the 3d printer (slm printer), it is possible to print final ready to use aluminium or steel magazines.
It would be just as easy, and result in a more durable magazine, to make a die to stamp thin steel plate. Magazines are easily made with basic machine shop tools - simple forming and a couple of rivets and presto.... Sourcing the springs would be an easy endeavor.