Shooting in the rain

M

mks

Guest
On Saturday at Buckcreek, I had my first "opportunity" to shoot in competition in the rain. The raindrops were falling pretty much straight down, and during the 10 minute, 200 yard match, it got stronger and then subsided. As the rain increased, so did the difference between POI and POA. The deflection of POI was up to 2" low and right (about 45 degrees) of POA. The effect was consistent through 5 record shots and 7 sighters, so I don't think it was just my poor shooting. It's easy to understand the downward deflection, but the rightward deflection is more difficult to explain. If the rain acted like a downward wind, the sideways deflection should be to the left.

It could be that I overlooked a slight left to right wind. Honestly, I was just chasing sighters during that match and not looking at flags. But the wind, if there was one, would have had to have been very strong to cause that large a rightward deflection, particularly if it had to overcome leftward deflection from the rain also. There could be an important external ballistics lesson to be learned here, but so far I am confused. Brian, can you help me out?

Thanks,
Keith
 
IMO the deflection is the result of the "downward wind" having to to somewhere. You're right that there's a downrush, now picture where it had to go. My guess is that the terrain was pitched or open on one side. The "wind" floods the area and has to vent somewhere, it can't continue downward! :)

al
 
Rain

I have had the 'opportunity' to shoot in the rain many times. The problem isn't the condition, the problem id suddenly having a shot go one inch from the group at 100 yards.

I have read all sorts of theories on how the rain affects bullets. Some say the bullet never gets wet, I honestly do not know.

But, as a competitor, I know bad things can happen when you are forced to shoot a relay in the rain. Very bad things.........jackie
 
alinwa said:
IMO the deflection is the result of the "downward wind" having to to somewhere. You're right that there's a downrush, now picture where it had to go. My guess is that the terrain was pitched or open on one side. The "wind" floods the area and has to vent somewhere, it can't continue downward! :)

al
Click to expand...

Al,
Buckcreek is reasonably flat with trees on left and right. The center of the 200 yard targets are about 4-5' off the ground. I agree that the air has to turn before it hits the ground. However, I am skeptical that it must turn that much at 4-5'. The raindrops, which I am guessing is the bigger factor, fall all the way to the ground.

Interestingly, I noticed a puff of vapor out a few feet from the muzzle with each shot, almost like I was shooting black powder, except it didn't last nearly as long. Maybe the bullet was impacting raindrops, or maybe the high pressure was causing condensation.

Nonetheless, there is something that I am missing. There was at least one 50-4x shot in the same rainy match. My shots were not only deflected, but also scattered more. 4 x's seems incredible for those conditions. I want to know what that shooter knows!:D

Thanks,
Keith
 
The chances of hitting a raindrop are thin-to-none. Of course it's possible ....... you could get struck by lightning too, but if a bullet DOES hit a drop it's going nowhere near the group!

Yes, the puff is condensation.

As far as the lateral dispersion, it nearly has to be a wind condition related to the storm.

I shoot in the rain a lot, it's one of the most consistent conditions possible.

IMO :D

opinionsby

al
 
Why would not the flow of water falling cause a downdraft of air being pushed aside/downward as the water droplets pass through it. One thing our flags do not indicate is downward movement of air. With uneven terrain and/or heavy enough rainfall, there may also be some convection currents in any particular direction when that air contacts ground level. Randy J.
 
Competing in the rain

jackie schmidt said:
I have had the 'opportunity' to shoot in the rain many times. The problem isn't the condition, the problem id suddenly having a shot go one inch from the group at 100 yards.

I have read all sorts of theories on how the rain affects bullets. Some say the bullet never gets wet, I honestly do not know.

But, as a competitor, I know bad things can happen when you are forced to shoot a relay in the rain. Very bad things.........jackie
Click to expand...

Jackie didn't Huckabe shot a potential world record agg the 2009 Crawfish in a torential down pour? I think it was a a .1580 agg if my memory serves me correctly. The pouring rain didn't seem to bother Sir Charles very much at all. :)

Has it been verified as of yet?
 
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Randy J. said:
Why would not the flow of water falling cause a downdraft of air being pushed aside/downward as the water droplets pass through it. One thing our flags do not indicate is downward movement of air. With uneven terrain and/or heavy enough rainfall, there may also be some convection currents in any particular direction when that air contacts ground level. Randy J.
Click to expand...

I think this is what Al is saying, too. I am becoming convinced that there was downward and rightward wind that I didn't recognize. That would explain the increase and decrease in the deflection during the match, too. Wish I had a video of the match to review. Another factor is that I was on the extreme left bench, so something could have happened there that didn't show up on the rest of the field of flags. I admit that after the first low and right shot, not seeing anything in the flags, I got tunnel vision and just chased my sighters. It didn't work, because as the effect increased I didn't hold off enough. Then as it decreased, I held off too much. The rain had subsided and the deflection was back to zero by the end of the match.

Thanks for your insights,
Keith
 
Lady Luck

333smitty said:
Jackie didn't Huckabe shot a potential world record agg the 2009 Crawfish in a torential down pour? I think it was a a .1580 agg if my memory serves me correctly. The pouring rain didn't seem to bother Sir Charles very much at all. :)

Has it been verified as of yet?
Click to expand...



In the 11 or so years I have been shooting I have seen a number of records broken and in some pretty tough conditions. The person having done it wasn't Superman but either saw something the rest of us didn't or Lady Luck smiled brightly on them. After all, the rest of us struggled, eh? :D.

A few of the people I know who have set records have all said the same thing, " I couldn't miss!". None of them have dominated before or since, I might add. Lady Luck, a great barrel and a well tuner rifle will sometime get er done.
 
Sir Charles

There is also another side to the Charles Huckeba saga.

At the World Championships a few years back, he was forced to shoot in the rain, and had a "rain shot" at 100 yards that darned near went an inch away from what was an excellent group.

After that, he shot so well that he still came out on top.

Like I said, I have no idea what happens in these circumstances. But, all you have to have is one "rain shot" to know that some bad things are just one shot away.........jackie
 
Rain Shots

But, all you have to have is one "rain shot" to know that some bad things are just one shot away.........jackie[/QUOTE]

I know know what you mean Jackie. At the same event I started off the first match with a decent .152 and then the skies opened up and scored a .606 in the next match during the down pour. It ruined my weekend. :(
 
alinwa said:
The chances of hitting a raindrop are thin-to-none. Of course it's possible ....... you could get struck by lightning too, but if a bullet DOES hit a drop it's going nowhere near the group!

Yes, the puff is condensation.

As far as the lateral dispersion, it nearly has to be a wind condition related to the storm.

I shoot in the rain a lot, it's one of the most consistent conditions possible.

IMO :D

opinionsby

al
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I'm not so sure al. If its raining out and bullets are flying, especially at long range, sooner or later a bullet will hit a rain drop. Think of exposing a bullet your holding in your hand to the rain for 10 seconds. That's like 10 rounds at 800 yards. Did the bullet get hit by a rain drop? Am I missing something?
 
I have to agree with Butch

I like shooting in the rain. I really don't think a bullet could hit a raindrop considering the vortex, or shock wave or whatever you want to call it would push the drop out of the way. Same as a swarm of gnats in front of the bench. Water in the barrel will certainly cause problems.
Bryan
 
Oh, if there's a raindrop in the road the bullet will fer'shure hit it! And will fer'shure land in the next ZIP code.............. There just ain't enough raindrops in the air for the bullet to have a bats chance of hitting one. Ask a bungee jumper, going down you can hardly find a drop, but comin' up's a B****! :D

Now if you're shooting out from under an overhang...... like a tin roof..... then you could have a problem as many of square feet of raindrops are concentrated to one edge.

al
 
I am with those that believe the vortex surrounding the bullet precludes it from ever touching rain .
I also think that the rains influence on the vortex causes the bullet to alter it's course while in-flight.
What I have trouble with is the old adage " shooting with rain blowing in the barrel will ruin it" (competitively speaking).
Wouldn't any water in the barrel be blown out ahead of the bullet?
Having shot a match during a severe thunderstorm....I was more concerned about running and getting done so I could cover the muzzle , than I was about dropping points.
Is there any credible evidence that gives credence to that adage?
 
Rain drops in bore

I don’t know about a bullet hitting a rain drop and causing a wild shot. But I can tell you that during the F-Class World Championships in Bisley, England a few weeks ago it started raining and the coaches called a halt for a while.

When they resumed fire the first shot was a complete miss at 1k on a 6x10 target frame. The next round was in the middle with no changes. Water in the bore? Further up the line several near misses occurred, all very low almost off the paper (3 foot from center). Teams that ran a patch thought the bore prior to shooting had no problem.
 
Hitting raindrops

I was curious about the possibility that bullets have little chance of striking a raindrop, so did some simple calculations, which I will share here. For a heavy rain, droplets are of about 2.5 mm diameter and have a terminal velocity of about 7 m/s (http://www.shorstmeyer.com/wxfaqs/float/rdtable.html). Using these values, to accumulate an inch of rain per hour, the volume fraction of rain in the air is just the accumulation rate divided by terminal velocity, which is very small at 1 x 10e-6. Next, the bullet will strike a raindrop if it samples during its flight to the target a volume large enough to contain a raindrop. (There is another component due to the vertical motion of the rain, but since the bullet velocity is so much greater than the rain velocity, this component is very small, http://news.bbc.co.uk/2/hi/uk_news/magazine/4562132.stm). Using a circle representing a 7.62 mm bullet just touching a 2.5 mm raindrop around its circumference (a circle 2.5 + 2x7.62 mm in diameter), the volume the bullet samples is a cylinder of this diameter and 200 yards long for a target at this distance. This volume is 45.2 x 10e6 mm^3, which multiplying by the volume fraction of rain, can be expected to contain 45.2 mm^3 of rain. Since the volume of a 2.5 mm raindrop is 8.18 mm^3, this is about 5.5 raindrops.

So a 30 cal bullet can be expected to interact with about 5.5 raindrops on its way to the 200 yd target in a strong rain. Raindrops that it crashes into at short range might throw it farther off course than those it barely touches at long range. Only in light rains of less than 0.1” per hour would there be a chance of hitting less than one raindrop on average.

Cheers,
Keith
 
I haven't seen a change in point of impact from rain in my own shooting but I always have an opportunity for sighter shots in my games. I have seen the effect of wind driven rain in the muzzle shifting point of impact in a repeatable way. My observation was the affected shots went out about 2 moa at 10 o'clock.

A friend who was deployed in Honduras in '84 said the snipers in his unit did change sight settings for rain on their M21's but not their Barrett 50's. (They had a rainy season). He doesn't know what the change was but they worked out to just 600 yds.

At the 600 yd Nats a few years ago I listened to a rainy relay from the yard outside the Varmint Hunters offices. It's a few hundred feet from and elevated above the left end of the firing line. From that elevated position you could track the bullets path by sound as they ripped through the rain on their way to the target. Sounded like high speed bacon frying on the move. I don't know if bullets touched rain drops or were effected by them, but the bullets sure had an effect on the droplets.

rwiw

Greg
 
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