I think you are referring to the Italian one I was discussing. It was a prototype being shown by its designer, who was practicing for the rimfire event. A really keen cammed, pantographlike mechanism that was smooth and translated the gun's sweep easily far beyond the span and height of the target. Though it was a joystick type, it used two separate systems for the motions that were cleverly interlinked. He said they will be made for sale, but the price estimate was pretty high to me. He didn't seem to have any hesitance in showing us the workings of it though. I tried to get a better look the second day, but never spotted the rig again.