[MarkCO]

There are two questions really.

With a moderate speed .308 match bullet, humidity going from 0% to 100% will equate to 1.5 to 2" difference in drop on the bullet at 1000 yards. In reality, it is minimal, but it does have an effect.

With a .22 caliber match bullet, the difference at 1000 yards is on the order of about 1 inch. Still not a huge affect.

As for actually hitting a rain drop, not going to happen while supersonic. The air at the tip of the bullet is heated and is a laminar wake. Displacement and sublimation of the rain drops occurs making actual contact with the bullet a mathematical improbability so high that it should not even be considered.

Testing has shown that air loaded with water (high humidity) has beneficial fluid dynamic properties to a bullet in flight. Shooting in 50% or higher RH will actually produce slightly smaller groups than perfectly dry air.

Wanted to add this. High humidity does very minimally reduce the MV at which the bullet leaves the bore, on the order of a few fps. But once we leave interior ballistics and go to exterior, the humidity is beneficial.