Im sure this has been covered not only here but in many forums over the years but I thought I would report my findings.
Today I was firing 32gn .204 projectiles at roughly 3900fps during light rain. First shot hit the target like a shot gun. Bullet exploded.
After that bullets consistently hit lower and to the direction of the wind which was clearly visible by the rain, although the wind was not bad, maybe the rain exagerated the effects onto the projectile?
I adjusted for this factor and I was back on target. Then when the rain had stopped the bullet shot the opposite to the adjustments I had made and shot high and in the opposite direction of the wind. The adjustments were reversed.
Re-adjusted and back on target.
Next it began to rain really heavy with no wind. Bullets impact shifted spot on vertically but two inchs low.
Target distance, 150yrds
Me scratches me head