I read the barrel is good for 5-6 shots of .380. Then you throw it away and insert a new barrel. It’s designed to be easy to replace. I think barrels can be made in different calibers. But not big calibers. Yet. This was just a proof of concept model.
Knowing how the Internet culture works, it’s just a matter of time before someone designs a semi-auto version. Changes in design and materials will certainly bring bigger calibers into play. I can see someone developing a material specifically to print barrels that withstand high pressures. Watch and see how clever geeks and hobbyists are when presented with a challenge.