Home Forums Hunting & Shooting Hunting Optics How does rain affect point of impact and accuracy

I had hoped to test 6 different .257 Roberts factory loads in my Model 70 today, but it will be raining all day.

Got me to thinking, how does rain affect point of impact and accuracy?

Bushmaster1313,

Perfect day for you to teach us. Go for it in the rain.

That has always caused me wonder as well. In googling, I came up with the weight of an average raindrop as being about 1.3 grains (if I did the math correctly - it said .003 ounce, so I divided 7000 by 16 and then took that times .003). Another source said that a raindrop hits Earth with a force equal to 349 X its weight. That comes out to about 454. Naturally, I don't have the faintest idea what any of that means. Would someone who understands this stuff and possesses great patience explain what effect one raindrop striking a given bullet (lets say a 180 grain .30 caliber starting out at 2700 fps) would have upon it? (Please try to keep it simple so that the slow among us can sort of understand the explanation - thanks in advance.)

Would it ever hit it? Pressure in front of the bullet should push it out of the way, correct?

i've heard that rain will raise POI a tad, but i have not been able to see any difference.

It dosen't do anything , the bullet is not in flight long enough,

Yet it is flight long enough for wind to affect it? Not being argumentative - I really am this dense.

My take is this...I can't for the life of me get it to change my poi @ 400 yds to less than minute of deer.

Not today.
I want to find out which factory load shoots best and I do not want to be bothered by the weather.

Correct. Based on reports from competitors, every now and again you can get a bullet to hit a rain drop (probably a really large drop, at that) that throws off the POI by a bit, but it's a very rare thing.

The pressure wave in front of the bullet, combined with the short TOF, both favour the likelihood that the bullet never touches a drop of water when you go shooting in the rain.

The wind is a constant pressure on it. Raindrops have too much space between them.

just forget it and go back to bed, you will nee the rest in the morning.

I shoot service rifle competition at distances out to 600 yds. with .223, rain, snow, or shine. I never consider the impact of the rain itself... I'm currently shooting master level scores.

If the pressure wave pushed the rain drop out of the way, Sir Isaac says that the reaction on the bullet has to be equal and opposite the reaction of the rain. That a bullet moves in the wind whose air molecules are proportionately so much less massive says the bullet will move. Because center mass of the rain drop may be randomly distributed around the axis of the bullet means the deflection may be random. Whether or not the bullet's pressure wave moves the rain drop or the rain drop does indeed hit the bullet is not relevant. A bullet fired n the rain may deflect less than a bullet fired into grass or brush, but it will deflect in the same manner with the same random dispersion.

Having found a fair number of Barnes bullets butt first embedded into trees behind my targets I suspect that a very small upset is possible and may cause them to tumble and restabilize going backwards because of the drag of the upset. I doubt the stability is very good. Of the bullets found embedded, it looked like maybe 80% went in butt first. It might well be that this sample is not representative. It may be that only Barnes TSXs are prone to doing this. It might be that only a specific kind of upset triggered by very specific conditions can cause this.

The chances of a bullet fired at a deer hitting a large raindrop and deflecting enough to matter are remote. Deer are not usually out in the open presenting longer range shots in rain that has big heavy drops. Light mist, light drizzle with small drops and snow, yes. BTDT. Never seen or heard of a deflection.

Not necessarily. The bullet itself isn't touching the rain drop. The bullet is pushing air out of the way, which pushes back (Newton's law, which we call drag), whether it's raining or not. The air then pushes against the water droplet. The reactive force of the water drop back on the air molecules would be insignificant because that pressure wave is rapidly and constantly composed of changing air molecules as the bullet travels along, rather than the same air molecules travelling with the bullet in a wave. The force that the droplet exerts on the air molecules would not transfer back to the bullet in any significant way. This is because the bullet would already have travelled passed those specific molecules by the time they make it back to where the bullet was at the time of impact with the water molecule.

If the bullet moves the drop, the drop has to move the bullet. Not an option otherwise.

The bullet doesn't move the drop. The air molecules do. That's the point. The reason that impact with a drop doesn't deflect the bullet, is that the bullet doesn't actually hit the drop, the air molecules of the air pressure wave do.

If you hold a ping pong ball on the palm of your hand, and then take a deep breath and blow it off your hand, the ball moves and flies off your hand. Does the ball exert a reactionary force on your mouth?

Aw GEEZUZ Jordan! You gotta think about things 'fore you open your mouth. The only place for the energy to move the ran drop can come from is the bullet. No ifs. No ands. No buts. If the bullet gives up the energy to move the drop, the bulloet is effected. If the bullet does not move the drop it is unaffected.

If you've ever shot in the rain or very humid air you will see a sizable "tube" of disturbed water along the bullet's path. The perturbation of all that water and the change of state you see is energy given up by the bullet.

See the displaced air forming a ">" around the bullet? No raindrop is going to touch the bullet. Any possible effect the wave has on the raindrop which in turn could effect the wave back to the bullet is moot because by the time that would happen the bullet is well past the effected air molecules that started it.



Rain has no effect on bullets. In fact I prefer to shoot in the rain. Talk about being able to see trace...

If the rain does not touch the bullet and assuming the rain drop is in the bullet's path, please explain where the energy to move the raindrop comes from.

By your logic if I smack you upside the head with a stick to help you understand this, I did nothing to you, it was that damn stick.

Pay attention! There is one place for the energy to come from. One only. The bullet.