Remove the bottles. At the rear of the stock, locate the brass insert which houses the cocking return spring, There is a small set screw in the stock which protrudes enough to prevent the brass insert from coming out. A few CW turns will put it below flush & out of the way. There is a set screw in the brass insert, remove it and the spring will also come out. Thread a bolt (5mm ?) into the brass insert and pull it out. Take out the cap screw near the gauge and the stock should be ready to remove.