Well, there were quite a lot of obstacles.

First, although 1364 might be a reasonable point in time in which you could say that hand cannon were being used, the recipe and manufacturing method for black powder would not be able to produce a consistent propellant until later, in the mid 15th c. So, small arms that could be aimed, used for hunting etc. arrived then.

For about 150 years after that there was the gradual development of a system of mechanical ignition, from matchlocks to wheellocks to flintlocks. A mechanical system was the only one that was really practical before the science of chemistry began to be developed in the 19th c., and because of that obstacle gunsmiths had to be content with making the flintlock mechanism itself more and more refined. That refining lasted quite a long time, more than 200 years, and the late flintlock were quite impressive - some of the ones by Durs Egg, for example, were so well-fitted and well-designed that they were almost waterproof. It was only after more chemistry was known, and the Industrial Revolution got under way, that more possibilities were available and really after that there was pretty fast development. The first experiments with percussion ignition, by Alexander Forsyth , were circa 1806, and only about 35 years after that the first breech-loading bolt action rifle was put into the hands of an army, the Dreyse needle-gun.

The impediment to any breech-loading gun in 1841 was, though, the fact that high-pressure gases could leak around the breech , something annoying or actually damaging to the shooter. The solution to that was the metallic cartridge. Brass cartridge cases had been made long before, but working out how to form and mass-produce strong brass cartridge cases and work out how to add the percussion ignition to the case was not quickly solved. There would be a lot of dead ends ( like Ambrose Burnside's externally-ignited backwards-tapered case) and weak designs ( like the Martini-Henry 577-450 composite cases) until center-fire cartridges became very practical and more common , circa 1870. Once there were strong center-fire cartridges, box magazines were also possible, circa 1880. The last development was the recipe for smokeless powder. This created the need for actions made of stronger steels that could take the greater pressures , but it also meant that guns did not become fouled nearly as fast, and so auto-loading guns really came along quite quickly. From the general adoption of smokeless powder circa 1890 it would be only 10 years until John Browning patented his first semi-automatic Model 8.

TL:DR The Industrial Revolution brought knowledge of chemistry and better manufacturing technology, until then guns were limited to mechanical ignition, and metallic cartridges were not practical to produce.