Seen a few different hand wheel style woodworking and guitar repair vises and their occasional use for scope mounting, cleaning, etc. Anyone here using one?

https://www.stewmac.com/Luthier_Tools/Types_of_Tools/Vises/Guitar_Repair_Vise.html

Those are often called Pattern Maker's vise.

WoodRiver Patternmaker's or Gunstock Carving Vise

MidwayUSA used to sell them as the Wheeler Engineering Patternmanker's Vise. Larry Potterfield uses one in several of his gunsmithing youtube videos.

Kinda the opposite for me, I use a protektor rear bag and lead sled weight bags, along with lead shot bags, lead ingots, etc. quite often when doing guitar work. Protektor bag is great for supporting the neck while doing fret work, changing strings, general setup type stuff. The weighted bags are handy for glue-up "clamps", etc. I see no reason that the vice / clamp you're referring to wouldn't work just fine for some gunsmithing work.

I've got a Pattern Maker's vise similar to the one below in the shop, yet to be mounted. Cool part is that the jaws can be angled/tapered to accommodate taper in the forearm of a rifle stock.

Pattern Makers Vise

Tag

I got this inexpensive carpenters vice and added two larger pieces of 3/4" thick wood with rubber glued to insides of wood.

https://www.harborfreight.com/hand-...inch-portable-carpenters-vise-95203.html

Seems like it would be a little clunky for rifle stock work.

It may well be. Still need to get it mounted to a solid bench.