ORIGINAL: Pavomesa
I don't have the exact trajectory figures before me but I can tell you it's pretty close to the truth. Bullets don't fly in a straight line, of course. Neither to they come out of the barrel and start dropping. Your gun actually launches bullet slightly upward (depending on how far you are sighted in) and the bullet goes up for a while and then finally starts curving downwards.
Actually, gravity begins working on the bullet immediately. If the barrel is perfectly level, then the bullet does "come out of the barrel and start dropping." Sighting systems are set up such that, when aiming, the barrel has a slightly upward cant, thus propelling the bullet above the line of sight. Gravity then works to bring the bullet back to the line of sight at the targeted distance.