pawpaw, The tool is easily made from a 1/2" or 9/16" open end wrench. I made this tool approximately 35 to 40 years ago and it has served me well many times. The end to the "left" is the one to be duplicated. You need to open the inside jaws to slightly less than 5/8 inches so it fits the Remington nut tightly so there is no "slippage". The jaws themselves are narrowed to 3/32" each. The outside of the jaws are "relieved" to get around the action bars without damaging them. You can see how much from the photo. I used a grinding wheel and files to make my wrench.....................Dick