Volley gun
Two notable artillery-sized volley guns were developed in the mid-19th century, although neither was particularly successful in practice. Developed in the 1860s and based on an 1850s design by a captain Fafschamps, the French mitrailleuse is an example of a multi-barreled volley gun that could fire all of its barrels simultaneously or sequentially over a short period of time. Also developed in the 1860s, General Origen Vandenburgh of the New York State Militia designed a weapon that had eighty five parallel .50 caliber rifle barrels. After failing to sell the weapon to the United Kingdom, he reportedly sold a small number to the Confederate States of America, although there is no record that they were actually used. One Vandenburgh gun was located at Fort Fisher, North Carolina, and another reportedly at Salisbury, NC.
Volley fire
Although volley fire is most often associated with firearms, the concept of continuous and concerted rotating fire may have been practiced using crossbows since at least the Han dynasty as described in the Han-Xiongnu Wars in the Records of the Grand Historian, although it was not until the Tang dynasty that detailed illustrations appeared. During the An Lushan Rebellion the Tang general Li Guangbi successfully deployed a spear crossbow formation against the rebel cavalry forces under Shi Siming. In 756 Shi Siming raced ahead of the main army with his mounted troops to intercept Li Guangbi's Shuofang army near the town of Changshan. Li took Changshan in advance and set up his men with their backs to the town walls to prevent a sneak attack. The spearmen formed a dense defensive formation while 1,000 crossbowmen divided into four sections to provide continuous volley fire. When Shi's cavalry engaged Li's Shuofang army they were completely unable to close in on his troops and suffered heavy losses, forcing a withdrawal.