It is says that the 14mm caliber cartridge was developed at the same time with the 20×130mm of the Type 71 anti-aircraft gun.I am still looking for more information about it.（By the way.Thanks @Sheng for the information about this cartridge.）
on your picture the “14mm” case look little slimer than the 14.5x114
Magnum, as per the inner case neck it appears to be a 14.5x114 no?
But as you are speaking of the 20x130:
Do you have more info, images and/or diagrams on that one???