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Thread: Does rain mess with accuracy?

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    Default Does rain mess with accuracy?

    How much does rain mess with bullet trajectory? I have not found much difference with a light rain to about 200 yards. I have not shot much in heavy rain, until last night that is. I had a HORRIBLE range day. I hope and hope it was the rain.

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    This is a great question and I have absolutely no idea what the answer will be. I'm interested in what Murphy has to say about this one.

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    Quote Originally Posted by Daved View Post
    How much does rain mess with bullet trajectory? I have not found much difference with a light rain to about 200 yards. I have not shot much in heavy rain, until last night that is. I had a HORRIBLE range day. I hope and hope it was the rain.
    Yes it does, it’s more a function of drag than deflection but both do happen. It makes your bullet slow down sooner than it would in just air. It takes a somewhat heavy rain before it becomes noticeable at a standard 100 yards but when you start pushing through 300 or 600 yards of rain it makes a huge deference.
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    It will affect accuracy and trajectory.

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    One of the major shooting magazines did an article on this a few years back, shooting through a sprinkler. Wish I could remember for sure which one. I want to say it was Shooting Times. Anyway, I can't remember the details, but it did show that there was an adverse impact on accuracy.

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    Default Yes

    anything that casues resistance or friction will alter bullet path.
    However, my rule is pretty simple - if its clearly visible in the scope it is probably not going to make enough difference in flight to cause a problem.
    Most game under 200 yards should have a large enough kill zone to offset any deviance.
    My son shot his 300 win mag in a steady drizzle last weekend and at 100 yards put 3 in a 1.25 in group - at 200 threw 1 / 5 inches right, then 2 in bullseye!
    He had not shot this gun for 5 years - same reloads he used 5 years before.
    Point is - target was clear enough to see well - bullets had little deflection.
    Beyond 200 yards I would have to ask myself if a shot in a heavy rain was really ethical or not anyway? Heavy snow and high winds also limit my distance of comfort....

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    Down here in 'rainy' country we just don't tell the deer and they don't seem to notice the difference.

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    I once tried to dispatch a coyote that was caught in a foothold trap from a distance of under 200 yards. It was raining cats and dogs and I felt the need to put the critter out of his misery. For love nor money I could not hit him with dads 222 shooting 50 Hornady SX bullets. No doubt in my mind that they were detinating on the big rain drops or tumbling or something.

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    Shouldn't make a difference. A lot of it is about time in flight. More or less it takes about .20 seconds for a bullet to cover 200 yards. If you strobed rainfall for .2 seconds you would see the actual distance between individual drops along a very narrow corridor is pretty wide, the odds are quite small that an object .308 x 1" would actually contact or coincide at a specific instant of time with any droplets would be very smalll. The potential surface area is actually much smaller than .308 x 1 because of the pressure ridge that completely envelops the bullet. A drop has zero chance of contacting the bullet other than at the exact tip of the bullet due to the pressure ridge surrounding the bullet. I have read that high speed studies show that even with a direct hit the pressure ridge in front of the bullet will split the droplet. Minimal out to 200yds. but an argument could be made that there may actually be less drag when it rains because the atmospheric pressure drops during rain, 28.8 vs. 29.92 kind of thing, less atmosheric pressure more velocity.

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    Rain will affect accuracy and trajectory

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    Anytime two objects in motion come in contact with each other then both objects are going to be diverted. The magnitude of the diversion is directly related to the mass, structure and speed of the objects involed. A bug vs windshield would be nill to the windshield but hell on the bug. A light weight frangible bullet vs raindrops the size of marbles........I don't know!

    There is no way in heck that I can make myself think that those bullets were getting to that coyote through that down pour without hitting rain drops. A thin skinned Hornady SX bullet will go off on a blade of grass. For that matter Hornady's manual warns about driving these bullets in excess of 3600fps because they can come appart in flight from friction building as they try to slide through dense air.

    All I know for sure is that I sat in grandpa's hayloft for 20 minutes waiting out the storm. When the storm blew over and the rain quit the first bullet that flew out the haymow door founds its mark.

    Maybe in general a 308 bullet won't be affected in light rain. Maybe my situation was extreme and above the norm? I don't know. Maybe the next time that we have a nasty ole Iowa thunderstorm rolling in I will grab my 17 HMR and see if I can put this to test......without getting drenched, that is.

    I too look forward to Murhpy's take on this!

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    Rain drops are one of my favorite excusses on why my perfect X shot only scored a 5.

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    I have to agree with Ed. Chances of a bullet even hitting a rain drop in flight to 200 yds are slim... and if a rain drop were to come into the bullet's path, a supersonic bullet puts out a shock wave in front of it leading me to believe that a super sonic bullet's shock wave would disperse the drop and never really touch it. The bullet's mass is much greater than a rain drop and combined with it's velocity, with 2000-4000 ftlbs of energy, and gyroscopic stability, is not likely to be deflected in flight, IMO.

    http://en.wikipedia.org/wiki/Supersonic

    http://en.wikipedia.org/wiki/Shock_wave

    I have read some other reports of guys shooting out to 1000 yds in the rain with no apparent affect on accuracy.

    It would be interesting to conduct an experiment at the range some day.

    Good shooting and stay dry,

    -MR

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    Quote Originally Posted by MontanaRifleman View Post
    I have to agree with Ed. Chances of a bullet even hitting a rain drop in flight to 200 yds are slim... and if a rain drop were to come into the bullet's path, a supersonic bullet puts out a shock wave in front of it leading me to believe that a super sonic bullet's shock wave would disperse the drop and never really touch it. The bullet's mass is much greater than a rain drop and combined with it's velocity, with 2000-4000 ftlbs of energy, and gyroscopic stability, is not likely to be deflected in flight, IMO.

    http://en.wikipedia.org/wiki/Supersonic

    http://en.wikipedia.org/wiki/Shock_wave

    I have read some other reports of guys shooting out to 1000 yds in the rain with no apparent affect on accuracy.



    It would be interesting to conduct an experiment at the range some day.

    Good shooting and stay dry,

    -MR
    MR, You mean to tell me that I was just flat missing that coyote! Dang your depressing to talk to.......but it coulda happened! I never liked that old 340 Savage anywho. It took three men and a boy to pull the trigger!

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    Default Air pressure

    Just like climbing high effects accuracy due to the lower density of the atmosphere the pressure change between a warm sunny day and a miserable wet day will effect accuracy. Mainly trajectory.
    The effects of wind currents are a factor too which, no doubt, change from wet to dry conditions.

    So my opinion is, YES, wet weather does effect accuracy.

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    Quote Originally Posted by elmerkeithclone View Post
    MR, You mean to tell me that I was just flat missing that coyote! Dang your depressing to talk to.......but it coulda happened! I never liked that old 340 Savage anywho. It took three men and a boy to pull the trigger!
    EKC, I think you are a good enough shot to hit a coyote at 200 yds. Your story does puzzle and intrig me and I cant say for 100% certainty that rain doesn't affect bullets, but from the little bit of research I've done on the subject, it doesn't seem likely that rain would have any significant affect on bullets.. The math and the physics just dont *seem* to suggest it, as well as other testmonies I've read from guys who have shot in the rain. I could entertain the idea that maybe one one even two of your bullets struck rain drops, but after that the odds of all your bullets striking drops gets astronomical. A good way to determine the odds of a bullet striking a rain drop in .2 - .3 seconds is to hold one out in a rain shower and repeat the process a few times to see how long it takes to get hit by a drop. My guess is that in a heavy rain it would take at least a couple of seconds on average, which would make the odds of striking a drop about one in six to ten in 200 yds. and then there's the whole shock wave thing and KE, etc. Lead has a specifc gravity of about 11 and copper about 9. So your average bullet is going to be about 10 times more dense than water. Your 50 gr bullet will probably have about 1300-800 ftlbs of KE from muzzle to 200 @ 3500 fps. Not a whole lot of energy as most bullets go, but I still dont see a 5-10 gr water drop hanging in space, having much of an affect.

    Maybe you were getting some sort of rain mirage???

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    Quote Originally Posted by maarty View Post
    Just like climbing high effects accuracy due to the lower density of the atmosphere the pressure change between a warm sunny day and a miserable wet day will effect accuracy. Mainly trajectory.
    The effects of wind currents are a factor too which, no doubt, change from wet to dry conditions.

    So my opinion is, YES, wet weather does effect accuracy.
    Weather really has no affect on accuracy as far as external ballistics go. Some enviromental conditions do have an affect on trajectory and POI at longer ranges, but at 200 yds, atmospheric conditons, other than wind, will have no noticable affect on trajectory or accuracy. Wind and calm can be and are both experienced in rain and on sunny days.

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    Couple things come to mind about this no effect theory.

    First the idea that holding a bullet in the rain for 2 seconds is the same as a bullet moving through rain is a bit flawed. This idea has been tested by many labs and they always find that any object moving through the rain gets vastly more contact with droplets than a static object. By the object moving it is effectively increasing its surface aria it will come in contact with. For easy math say a bullet has a 1Ē frontal aria and falls at 10 feet per second then our bullet will cover 120 square inches of aria in 2 seconds. Same bullet traveling 200 yards will cover a frontal aria of 7200 square inches in the same time, so our bullet exposure just grew by 7000square inches on us.

    Next is the shock wave thing, I donít have anything to back this up but I bet itís out there. Since the bullet pushing through the air is pushing the shock wave stands to reason that anything that effects the shockwave would affect the bullet also, so the shockwave may actually be increasing the rains drag effect by making the frontal aria bigger thereby interacting with more rain droplets.

    I may not understand how but do know from my own experience that rain degrades accuracy. Itís not a huge effect and wonít matter for most shots under 200 or 300 yards, but push it on out, or turn the volume of water up and it becomes very very noticeable to the shooter.
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    I have shot in the rain. If you've ever been squaded to shoot the long line at Camp Perry when the squalls roll off the lake Erie, you'll learn about shooting in the rain. It is also a great time to watch the vapor trails of bullets as the arc their way to the target boards. When the rains start they will usually just be out near the lake and may be sunny back at the firing line. As long as the target stay put, we keep shooting. I am absolutely convinced that rain drops adversely effect accuracy. I few little rain drops can cause two foot difference in POI at that 600 yard line.

    It is also an absolute wonder to watch when the fog rolls over the levie with crossing wind to see the bullet flight as it curves out into the wind as much as ten or twelve feet then curves back to the target riding on the wind. At impact, you can see the steam leave the target backers with a puff. When you spot for a team mate, and conditions are right, you can see this easily.

    I do believe that the same holds true for rain shooting as for the so called brush shooting. Some bullets at certain velocities do better than others. Faster, smaller, lighter weight and more pointed (Spitzer) bullets are more easily deflected by obstacles along the path. Also the obstacle closer to the muzzle has a greater effect than when a bullet encounters an obstacle near the target. (This is due simply to the angular deflection which is compounded over distance.) It would make sense, and is consistant with my experience that rain serves the same as weeds, tree limbs, etc. but likely to a lesser extent. I would say that a 50 grain spitzer in a 222 or 223 would be deflected more easily than a 165 grain round nose, 308. And of course if using a 500 grain flat nose in a 45-70, EKC could have dispatch that coyote in a monsoon rain.

    It would not be a good excuse for shooting a six, some 14 inches out of center, at 25 yards, with a 45 ACP but it has been used many times at the long line at Camp Perry and other ranges around the country.
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    Quote Originally Posted by ADfields View Post
    Couple things come to mind about this no effect theory.

    First the idea that holding a bullet in the rain for 2 seconds is the same as a bullet moving through rain is a bit flawed. This idea has been tested by many labs and they always find that any object moving through the rain gets vastly more contact with droplets than a static object. By the object moving it is effectively increasing its surface aria it will come in contact with. For easy math say a bullet has a 1Ē frontal aria and falls at 10 feet per second then our bullet will cover 120 square inches of aria in 2 seconds. Same bullet traveling 200 yards will cover a frontal aria of 7200 square inches in the same time, so our bullet exposure just grew by 7000square inches on us.

    Next is the shock wave thing, I donít have anything to back this up but I bet itís out there. Since the bullet pushing through the air is pushing the shock wave stands to reason that anything that effects the shockwave would affect the bullet also, so the shockwave may actually be increasing the rains drag effect by making the frontal aria bigger thereby interacting with more rain droplets.

    I may not understand how but do know from my own experience that rain degrades accuracy. Itís not a huge effect and wonít matter for most shots under 200 or 300 yards, but push it on out, or turn the volume of water up and it becomes very very noticeable to the shooter.
    AD, with due respect, a bullet's surface area is not increased by its movement through the air. Any two objects can only occupy one place in space and time at any given instant of time. Either they bullet and the drop occupy that space in the same instant or they dont. You may be right about the shock wave affecting the bullet's drag when encountering a drop... hard to say.

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