I do not have a regular gun vice but have the typical 4 inch bench vice with anvil, 5 heads for my Pana-Vice bases, 1 vacuum base, one mounted on a movable base plate, and one mounted to my work bench. Of the 5 bases, I have one with steel jaws, two with soft jaws, one that opens to about 6 inches with rubber grips and one that holds circuit boards, I also have a 2 inch and a 4 inch flat vices for milling or drilling work. Plus bigger vises for bigger jobs.
I really like the Pana-Vise system for versatility and portability. A some point I want to get a lead sled for scope and sighting work.