The .14/22 Short is apparently a wildcat cartridge created by necking down the case of a .22 Short in order to accept a .14 caliber projectile. It's unclear whether it's a novelty, perhaps simply for display purposes, or if it (or a similar creation) has ever actually been fired or put through extensive testing.
We found essentially zero information on it, other than discovering the cartridge in a picture in a thread on the Field & Stream Questions and Answers forum.
At the bottom of that thread, the user "Extreme Accuracy" references their website: 14caliber.com, as well as the picture above. That site contains the same picture, and it also references their other website, ExtremeAccuracy.net. Unfortunately, the latter is no longer up, but even using Wayback Machine, we were unable to find any information on the .14/22 Short cartridge.
This page on ExtremeAccuracy.net once again shows the image above, but we see no other references to the cartridge.