Ammunition is handloaded, using modified parent cases and the gunsmith-provided wildcat dies.
The parent case is well lubricated and forced carefully into the reloading die for the wildcat caliber.
This meant that for a given powder capacity, any cartridge based on the .348 case would be shorter than one made using another parent case.
This method of fireforming left the newly formed cases slightly shorter than the parent cases.
There are four "series" within the Whisper Family, each using a different parent case.
Several more cartridges have been developed using the .308 Winchester as a parent case, some becoming very popular for hunting, particularly in North America.
To keep costs down and promote an acceptable recoil level blowing out the parent case was renounced.
A wildcat from Europe that uses the 8x68mm S as its parent case is the .30 Kovacs.
This was the parent case for many other later cartridges, such as:
The .284 Winchester was created around 1963, but never really caught on, except as a parent case for the wildcat 6.5mm-284.