If you make a .410 gun yourself (like printing it from a 3D printer) is it still illegal? The PDX Round ammunition itself isn’t illegal...
The Judge itself is illegal, not the ammo. It is classified as a “short barrel shotgun” in California, so even if it is loaded with .45 rounds (which it also shoots), it would still be illegal as I understand it, although I doubt many LEO’s even know this distinction.