I had a thought about trajectory: The common theory is that trajectory is a smooth arc from muzzle to target. Is that really true? Could it be that a bullet wavers up and down along that arc due to atmospheric changes? As a bullet follows trajectory it rises and drops. Along the rise to apogee and descent to target there are minute changes in air density which could cause the bullet to jump up or drop a little. Also, could the makeup of the ground over which the bullet travels have an effect? Different substances on the ground reflect heat in different ways thereby affecting air density which could affect bullet travel. Wind currents may play a part as well. We know the effects of crosswinds. Could wind move a bullet up or down as well as sideways? Bullet size, shape and speed may have an effect. So, my question is: Is trajectory a smooth arc or a wavering path? How about some thoughts from any Physics types or ballistics experts out there.