While we often talk about the obvious role of the military in the development of guns, I don't think enough credit is given to the role non civilians played in the development of firearms. The military often adapted and utilized inventions that were first made by civilians for the civilian market.
* The percussion cap was invented by a civilian, an avid bird hunter who was tired of missing his favorite quarry because of the delay between the spark of the flintlock and when gun actually fired.
* The metal cartridge was invented by civilian gunsmiths, and first used in civilian applications.
* The Henry repeating rifle, ancestor of the famous Winchester rifle, was designed in 1860, before the American Civil War began, and was not used by the military. The first customers were civilians.
* The first rifles were long used mostly by civilians rather than the military
* The snaplock, and snaphance firing mechanisms, ancestors of the flintlock, were developed in the 16th century as much to meet the need of civilians than than that of the military. The expensive wheellock as well was developed as much for the needs of hunting and defense as for military applications, based on the richly decorated models you can find. When the royal French gunsmiths invented the first true flintlock, flintlock firing mechanisms had been around for more than a century.
Without this active civilian market to drive innovation, would European firearm technology have advanced as rapidly as it did? Hunting was a popular past time in Europe not just for the rich, but for the merely well off as well (think Alexander John Forsyth, inventor of the percussion cap) and in frontier areas like the Americas, an essential tool.
And could the real reason other areas were slow to switch from the matchlock was because those regions, like India and China, lacked a large group of well off civilians (hunters and others) who were driving innovation. While I am sure the rich nobles engaged in hunting in other areas, what about the less noble, the merely middle class, in India and China? Was hunting also a popular past time for them as well, or if they did hunt, did they just prefer to use traditional weapons?
For example, the crossbow was continued to be used and developed in Europe long after the crossbow ceased to be used in warfare (crossbows are still undergoing development today), while I don't see that same kind of usage and development in China after the crossbow ceased to be used in warfare. (The crossbows that continued to be used in China were by minority groups and the designs did not undergo significant development).
Could a lot the European firearm development have been driven by a civilian usage of a kind that did not exist in other areas? That European military firearm development often took advantage of the development work done for the civilian market? Just food for thought.