you might be able to use a rubber strap wrench. if you don't have one, you should be able to pick one up cheap at the local hardware or box store. or auto parts store. then when you put it back on, I usually put the stock between my feet and just "torque" it with my hands, tight. ive never had an issue getting one of my barrels off. and when switching the return to zero has always been inside of .1 mils