Anybody familiar with this process of forming cartridges without firing? I heard that Greyback Wildcats uses this process, but I don't know for sure.

the gibbs (not 505 gibbs) line of wildcats used this. using hydrolic or compressor oil, you attempted to not blow oil out the primer hole while pushing the shouder and taper around... you obvisouly couldn't change the neck diameter, as this would become a high pressure leak.

most folks found that take the neck out to a huge caliber, then forming a merger datum shoulder would allow for standard fireforming, with much better results.

jeffe

To add a little to what Jeffe said. The system was very simple. There was mainly two pieces. One screwed on to the bottom of a normal full length resizing die to hold the case and seal the bottom. The second was a piece that replaced the decapper assembly. Screwed in from the top and sealed the top of the die and around the rod. The plunger rod could move up and down. Anyway but the case in the die with and inert primer. Fill the case 3/4 full with medium weight oil (refrigeration oil was recommended) Screw on the cap and strick the plunger rod with a heavy hammer 3-4 times. Remove the case and clean run it though the die normally and load. Formed cases without wear on the barrel or the expense of powder and bullet.