 Complete the following phrase:  A long-range experimental cannon, the Sawyer gun, was installed at Fort Calhoun in mid-1861 during the Civil War. The weapon was rifled, and an illustration in an August 1861 newspaper shows it mounted on a high-angle carriage. The range of this weapon extended all the way to Sewells Point, more than three miles away where the Norfolk Naval Base is now located, the site of a Confederate earthen fort with bastions and a redan and three artillery batteries totaling 45 guns. The weapon was a rifled 24-pounder which would fire a projectile of 4248 pounds, one of several rifled artillery pieces developed by Sylvanus Sawyer; however, none of his designs were widely adopted. A weapon of this type was tested at Fort Monroe in 1859, and two different Sawyer weapons, a 24-pounder rifle and a 3.67-inch, were used in the Siege of Richmond of 186465, although the 24-pounder burst at the tenth round and the 3.67-inch rifle was seldom used. The 