Years ago, Rick Jamison published a magazine-sized book with do-it-yourself projects for shooters. One of them was a portable take down shooting bench. Be forewarned, it's too heavy to carry like a suitcase.
The top is of a standard shape, consisting of two layers of 3/4" plywood. The three legs are 1 1/4" pipe, 31" long, threaded on one end. The legs attach to the top with square plates which have had threaded pipe couplings cut at a 20 degree angle welded to them. That 20 degree angle of the legs and the weight make the shooting bench very stable. For me, the height is perfect if I sit in a lawn chair.
