The main reason why muskets displaced bows is that it takes a lifetime to train a good archer and you need to be fairly strong to use it effectively. Musket training is easy and it doesn´t matter at all how strong you are.
This article would agree with this view
The development of gunpowder, muskets, and the growing size of armies (and their consequent demand for less-trained levies) slowly led to the replacement of bows as weapons of war, supplanted by firearms, which were simpler for conscripts to learn and use, causing bows to be relegated to sport and hobby use.
http://en.wikipedia.org/wiki/Bow_(weapon)
The article of the musket is interesting as well, since it
sounds complex
The initial role of the musket was as a specialist armour piercing weapon .....
(Procedure)
Upon the command
"Prime and load", the soldier would make a quarter turn to the right at the same time bringing the musket to the priming position. The pan would be open following the discharge of the previous shot, meaning that the
frizzen would already be up.
Upon the command
"Handle Cartridge", the soldier would draw a
cartridge. Cartridges consisted of a spherical lead
bullet wrapped in a
paper cartridge which also held the
gunpowder propellant. The other end of the cartridge away from the ball would be sealed with a twist of paper.
The soldier then ripped off the paper end of the cartridge and threw it away, keeping the main end with the bullet in his right hand. (The idea that the ball itself was somehow bitten off the top of the cartridge and held in the mouth is a myth invented by modern historical novels).
Upon the command
"Prime", the soldier then pulled the dogshead back to half-**** and poured a small pinch of the powder from the cartridge into the priming pan. He then closed the frizzen so that the priming powder was trapped.
Upon the command
"About", the butt of the musket was then dropped to the ground and the soldier poured the rest of the powder from the cartridge, followed by the ball and paper cartridge case into the barrel. This paper acted as wadding to stop the ball and powder from falling out if the muzzle was declined. (The myth of spitting the ball into the end of the barrel from the mouth is easily disproved - as soon as it is fired, the barrel becomes extremely hot; it would be extremely painful to place the lips anywhere near the hot metal.)
Upon the command
"Draw ramrods", the soldier drew his
ramrod from below the barrel. First forcing it half out before seizing it backhanded in the middle, followed by drawing it entirely out simultaneously turning it to the front and placing it one inch into the barrel
Upon the command
"Ram down the cartridge", he then used the ramrod to firmly ram the wadding, bullet, and powder down to the bottom followed by tamping it down with two quick strokes. The ramrod was then returned to its hoops under the barrel.
Upon the command
"Present", the butt was brought back up to the shoulder. The soldier pulled the **** back and the musket was ready to fire, which he would do on hearing the command
"Fire". When the men fired they usually didn't hit a specific target, but the volume of fire was deadly within 20 meters.
This process was drilled into troops until they could do it by instinct and feel. The main advantage of the British Redcoat was that he trained at this procedure almost every day using live ammunition. A skilled unit of musketeers was able to fire three rounds per minute. This was the limit whilst loading to order as above, however an experienced individual could manage four rounds a minute if firing at will, such as in a skirmish situation.
http://en.wikipedia.org/wiki/Musket
Another interesting afterthought, if you can fire a bow 7 times as fast as a musket does this mean you need to train only 1/7th of the men?