The pivot bolt on the right/left arm that comes up through the base is run through the bottom of the jack it self. I then brought out a big washer to hold the jack down there and a wing nut so the whole thing comes apart for easy packing in and out from the range. So yes the jack is kind of bolted down. But your right, the weight of the jack is really all you need. I just went the extra because that way it can not tip over with one of my rifles on it. I figure I might have $5.00 in the whole thing. And that jack that was always in my way everytime I looked for something in the garage is now put to good use.
I was thinking in the one blind I use on my property, I could pack that out the day before and have a nice solid rest to do my shooting off of when them critters come sneaking up the trail towards the field to feed.

Does that sound fair?