Volley gun
The Ribauldequin was a medieval version of the volley gun. It had its barrels set up in parallel. This early version was first employed during the Hundred Years' War by the army of Edward III of England, in 1339. Later on, the late Swiss army employed it.
Volley fire
By 1548 the Ming had started fielding arquebuses after procuring knowledge of the weapon from the pirate network at Shuangyu. The military leader Qi Jiguang, who was at first ambivalent towards matchlocks, became one of the primary advocates for their incorporation into the Ming army later on in his life. After having suffered his first defeats at the hands of the wokou, he realized the vital role of this new weapon in combating piracy, for it out ranged their heaviest arrows. By 1560 he had invented a style of musket warfare similar to the Tang crossbow volley technique which he described the same year in his magnum opus, the "Jixiao Xinshu":