What is the parent cartridge, and basically, what is the process for making cases?? TIA

All of Rocky Gibbs wildcats are based on the .30-06 case. RCBS may still make a hydraulic case former but I don't know that for sure. I load for the .270 Gibbs by necking up .280 rem cases to about .35 cal then neck down in a .270 gibbs die. this will give enough of a false shoulder to headspace for fire forming. Gibbs cases can not simply be formed by firing a standard shell in the chamber. As an additional aid, I seat a heavy bullet into the lands to help headspace. Hope this was some help.

I have the dimensions for the Gibb's hydraulic case former, if you'd like to have them. Also, photos of how it's assembled and used. Just email me at...
ed@aement.com
Regards,
'puck

A hydralic case former is a less than satisfactory method of forming cases..Mostly it just spews oil all over you.

Just fire form your cases...One can build a fire forming gun from one of the cheap mauser actions and they work great...Jack Belk can give you the specs for building a fireforming gun..You fireform the case in your reloading sizer die screwed into the bolt action with the stem out of course...