Abstract: A tank mountable stock arm monopod for pneumatic guns or the like has an arm mounting saddle fastened to the compressed gas tank of a pneumatic gun with adjustable stabilizing straps. The arm mounting saddle has a pivotally mounted coupling that connects with the arm mounting saddle and the lower stock arm. The lower stock arm comprising of a cylindrical section that fits into the saddle arm coupling. The sliding upper stock arm is a cylindrical section smaller in diameter than the lower section enabling the sliding section to fit and move inside the stationary section in a telescoping movement, allowing the length of the stock to adjust to the user. A stock arm butt is pivotally mounted to the sliding stock arm opposite the stationary stock arm. The stock arm monopod is put into the monopod position by loosening the stabilization straps and spinning the apparatus 180 degrees so that the stock arm butt is pointing towards the playing surface.