Not as elaborate as the one in the video but I have used this to do some stock work. There is a piece of pipe for the top end that is lined with carpet that will fit over the nose of the stock. Tighten the all thread into the rear of the stock and tighten wing nuts.
Another way is to use large connecting rods (small block Chevy) with the big end fitted to a piece of pipe the right size acting as a clamp and then the small end of the rod rigged with a wooden plate to match the butt-stock and then the other small end with a cupped shape fitting fashioned to fit the nose of the stock.

Adjust the connecting rods on the pipe and clamp where you need them (you can get an angle) for working right or left and tighten your rigging through the small end of the rod to hold your piece. Clamp the pipe in a radial bench vise. To a bench in the middle of the floor if you have the space.
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