when was gunpowder used for firearms instead of fireworks?

Answer 1

Chinese military terms are often difficult to interpret, but the earliest recognizable gunpowder formulas are found in Wu jing zong yao (Essentials of Military Classics), edited in 1044 by Zeng Guangliang. The first true gun appeared about 1260. Many theories have been proposed as to how the rocket appeared. One is that the discovery was made when a Chinese soldier modified an ordinary incendiary "fire arrow."

For certain, Chinese chronicles contain numerous accounts of gunpowder weapons from the late Song dynasty, though it is often unclear whether they refer to rockets. The most famous examples are the flying fire arrows, or more correctly, flying fire spears, used by the Chinese against the Mongols in the siege of Kaifeng in 1232. Some authorities believe the devices were no more than thrown "flying fire" spears, or perhaps handheld lances that merely shot fire into the air; others contend they were true self-propelled rockets.

Answer 2

The first recorded use of gunpowder to launch a projectile was in 1100 or so. It was a Chinese 'gun'. It was a hollowed out hardwood tube that housed a small round stone. Some original 'guns' are on display at the Smithsonian.

Answer 3

It was an ancient Chinese "rocket" that used the gun powder.