one with the Parrott design, and one with the Rodman approach. The Rodman solid shot weighed 618 to 619 pounds and the Atwater solid shot 416 to 535 pounds. The weights of the Parrott projectiles are not recorded. In 1867, at Fort Monroe, the guns were tested with charges varying between 35 and 55 pounds until the guns failed. Table of Dahlgren rifled guns Estimated values are indicated by an asterisk. Estimates by . See also Armstrong Gun USS Monitor Notes References . Edwin Olmstead, Wayne E. Stark, and Spencer C. Tucker, The Big Guns: Civil War Siege, Seacoast, and Naval Cannon, Museum Restoration Service, 1997, Chairman of Maritime History, Kyle Rapp Ph.D, M.D External links Naval guns of the United States American Civil War artillery