shooting in the rain


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taliv
August 24, 2008, 06:48 PM
ya know, there's just something about laying out in the rain, shooting a precision rifle. all the pansies go inside and it's nice and quiet. get your zen on.

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bragood
August 24, 2008, 06:49 PM
I have to agree with you on that! Was shooting in a garand match last year and it rained all day and the firing line was not covered and no cover to be seen for miles. It was awesome though and I believe more should do it.

Jason_G
August 24, 2008, 06:56 PM
Never really did much target shooting in the rain, but I've sat in my share of tree stands during downpours. Deer usually bed down when there's a frog-strangler, but when the rain stops it is good to be on the stand. I usually try to sit it out unless there's no end in sight. I usually carry one of those plastic rifle bags for my gun in case it starts raining. What do you guys do about rust?

Jason

SlamFire1
August 24, 2008, 07:00 PM
Well, I am a pansie now.

When I was Hard Core, I would go out and shoot a highpower match in the rain. I was happy to shoot in the rain in local matches. At the end of the day, I would be covered in grass and mud, my equipment saturated, and I would have to disassemble my rifle completely.

There were times I had to use a blow drier on the eyepiece to my spotting scope. Because rain had fogged it up.

Now, if the weather channel shows rain, I ain't going.

Gone to the Pansie side.

telomerase
August 24, 2008, 07:11 PM
Seems that it would randomize your results at long range... hitting raindrops has to do something :confused:

Gene Kelly agrees with you though:

I'm shoot-ing in the rain
Just shooting in the rain
What a glorious feelin'
I'm happy again

marktx
August 24, 2008, 07:13 PM
Went out to the range last weekend when it was pouring down and had a great time. The firing line is covered so it was pretty simple to back the car up and pull the guns out without even getting them wet. Nobody was around to be distracting or ask a bunch of questions about those funny looking foreign guns. It was also a great opportunity to try out a few mags of tracers, normally wouldn't dare due to the fire hazard.

Only downside was a few of them chuck the shells way out in the rain. Oh well

jdc1244
August 24, 2008, 07:24 PM
Rain is fine, lightning not. Golf clubs and guns are a bad idea in a Florida lightning storm.

Jason_G
August 24, 2008, 07:53 PM
Golf clubs and guns are a bad idea in a Florida lightning storm.
Add "rod and reel" to that list please :D

Jason

jkingrph
August 24, 2008, 09:46 PM
Back in my college days, some 40+ years ago, a friend and I were shooting while it was sleeting.

Bartkowski
August 24, 2008, 09:51 PM
I usually carry one of those plastic rifle bags for my gun in case it starts raining. What do you guys do about rust?

Let it rain. When you go in for the day dry the gun and oil it up. I do carry a plastic sandwich bag for the scope if I don't have a cover for the lens. Nothings worse than seeing a deer, but having water drops blur the scope.

EShell
August 24, 2008, 10:10 PM
Rain has no effect on exterior ballistics. The shock wave that is pushed ahead of the bullet displaces raindrops and there is no appreciable loss of velocity or increase in drop.

Storms are no good to shoot (recreationally) in, due to lightning hazard and the typically higher winds that accompany storm activity.

A gentle rain can be very educational to shoot in, due to being able to actually see the wind in the slant of the rainfall.

Wet cartridges can show high pressure, and I've seen several occasions in which even factory loaded ammo will flatten primers, show ejector marks and be difficult to extract. I do not know the mechanism at work, but suspect it has to do with dampness increasing case head thrust.

nwilliams
August 24, 2008, 10:45 PM
I love being out in the rain, just not with my guns.

Its not that I have a problem with shooting in bad whether, I just worry about rust developing.

possum
August 24, 2008, 10:53 PM
yeah the other day i went out in the hurricane (as my wife likes to put it) it was clear when i went out and i knew it would probally rain but i didn't care i wanted to shoot by god. so i did, and the rain was horrible, but what a binch of fun it was, and for me the training dosen't stop because of a littele wetness. it was fun and i am sure that i will do it again.

tiger rag
August 24, 2008, 10:54 PM
Good info ESHELL
Thanks

takhtakaal
August 24, 2008, 11:21 PM
I was in a competition the other month, shooting steel at 200 yards through an EOTech in a driving rain storm. It was such that I could discern the spray-painted color of the target, but because the rain was in spots and rivulets on both sides of the glass, it was almost impossible to really focus. I managed to hit it twice out of five shots without magnification, and while it felt like a bit of an accomplishment, having to dry everything out was a PITA at the end of the day. I would have been just as happy to have done it on a dry day, thank you.

oneshooter
August 24, 2008, 11:22 PM
No thanks. I shot, and lived in a area where it rained six month at a time. NO fun.

Oneshooter
Livin in Texas

JImbothefiveth
August 24, 2008, 11:27 PM
If i had a stainless barrel, and a laminate stock, or shot under a tent I would, and I find outdoors in general to be better with rain. My favorite, though, is taking an old beater gun and shooting in ankle deep snow.

Matt-J2
August 25, 2008, 12:20 AM
It was snowing the day I bought my M44, so I took 2 boxes of ammo and killed a few Nazi logs. It's been in the rain as well, just seems to thrive in the snow. :)

jim147
August 25, 2008, 12:40 AM
I still go out in the rain sometimes, but I will more than likely be casting or reloading if it's going to rain too much.
If your worried about rain on you rifles wax makes the water bead just like on your car.

Jenrick
August 25, 2008, 12:55 AM
Place I used to shoot had a covered concrete pad pistol range surround on three sides by a berm that was taller then the roof. The berm during the summer is covered in 6' sun flowers, which makes being out there a little odd in the first place. Add in a frog strangler that had the water pouring in a water fall off all sides of the roof, and me not getting wet, it looked like Salvador Dali decided to paint a shooting range or something.

-Jenrick

rangerruck
August 25, 2008, 04:40 AM
I had the funniest thing happen to me once, while in the Army, in the Philippines, setting up a live fire mock ambush, on an overlooking hill. With my Lt. , Rto man, and me as a 60 gunner, with an asst. We were on a bare hill, hi above the zone. and the rain comes.... and just never relents. At one point the Lt looks at me, and there is a little river of water, that is running down the flat ground of this bare top, and the river is going rigth into the top of my BDU shirt, and continues on down my uniform,(laying in the pron pos) and is coming out my left pantleg, and continuing to make it's little stream, right into the top of the ground. And he looks at me, and the little river at the front of me, and the one coming out my pant leg, and we all just start breaking up, loudly!!!
We had to postpone the ambush, we couldn't stop laughing for about 20 minutes...We had been in the field a long time at this point, and man, we were all just really punchdrunk at that point, I imagine anything like that would make anyone laugh uncontrollably.

General Geoff
August 25, 2008, 06:40 AM
Rain has no effect on exterior ballistics. The shock wave that is pushed ahead of the bullet displaces raindrops and there is no appreciable loss of velocity or increase in drop.

This is not true, heavy rain does increase bullet drop dramatically.


Back to the OP, I shoot in the rain as often as I can. I enjoy rain in general, however, and usually go outside when it's raining just because.

EShell
August 25, 2008, 09:30 AM
Rain has no effect on exterior ballistics. The shock wave that is pushed ahead of the bullet displaces raindrops and there is no appreciable loss of velocity or increase in drop.
This is not true, heavy rain does increase bullet drop dramatically.
How far? What caliber(s)? Subsonic cartridges aside, if this statement comes from personal experience, I would have to think that either your rifle POI itself was directly affected (bedding vs stock warp as it took on water, for one example, reduced ammo temperature and reduced MV is yet another), or that the rain I've shot in must not be nearly as heavy as your's, which would be hard to believe due to target visibility.

There is also the aspect of other unseen environmental factors, such as station pressure changes. It is VERY easy to see 2 MOA or more change in drop at extended ranges due to air density alone. Running any ballistic program with variations on the "altitude" parameter will very quickly demonstrate this. Do you monitor air density (station pressure or density altitude) when shooting at extended range?

Mirage shifts POI upwards, sometimes almost imperceptibly, other times substantially, and there is usually no mirage during rain . . . could this have been the culprit?

We've spent quite a bit of time shooting out to 1,200 yards with .243s (105 Scenars), various 6.5s (.260/6.5-284/6.5-300Wby, all using 139/140/142 BTHPs), .308s (155 Scenars & 175 SMKs) and .300WinMags (210 Bergers) and, if we can still see the targets, drop data has been unaffected.

In fact, I've often seen the opposite and there have been times when drop is slightly lessened by the reduced density altitude that often accompanies this sort of weather, not to mention the fact that increased humidity further reduces air density.

There is a military report that I am unable to find at the moment that specifically indicates that the effects of rain on bullet flight are minor and takes a distant back seat to several other other factors.

And then, there's this collective experience:
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=694051&Searchpage=2&Main=63692&Words=rain&Search=true#Post694051
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=666115&Searchpage=5&Main=59723&Words=rain&Search=true#Post666115
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=466138&page=1

For these reasons and in light of our own experiences, I stick to my statement above and suggest that there were/are other factors involved if rain seems to be causing increased drop.

JImbothefiveth, if the ammo can be kept perfectly dry, the effects on the rifle's finish is the biggest problem I've seen. I have a Remington LTR that I can sit and watch rust, Badger rings seem almost impossible to protect and the effects on a rifle that is blued in a wood stock are worse than "ugly". For abusive conditions, I've gone to synthetic stocks (McMillan, Manners and HS Precision), and have had my last few custom rifles finished in Teflon.

PTK
August 25, 2008, 09:31 AM
I try to bring my Finnish M39 out in the rain now and then. The one I have is all beat up anyway, and saw combat almost for certain. I figure shooting it in the rain isn't a big deal. :)

rc109a
August 25, 2008, 10:46 AM
I don't like shooting in the rain, but deer hunting is fun. I have never seen so many out like I do when you get that gental shower. Not to mention that they cannot hear as well. I am sure Reloader Fred is one of those who loves shooting in the rain since it rains almost everyday at his place...

Dr. Tad Hussein Winslow
August 25, 2008, 11:41 AM
I do find it extremely odd that even heavy rain doesn't materially change the point of impact. You would think it would knock your bullets down, and have a much lower point of impact. It does cause some erratic shots, and hinders accuracy. But overall, accuracy can be acceptable in the rain, provided the wind is not crazy.

EShell
August 25, 2008, 01:03 PM
I will very quickly agree that the facts are counterintuitive to what we would all assume.

I would also venture yet one more potential explanation for drop blamed on rain that I had forgotten to mention above: Vertical spin drift due to crosswind. In rainy weather, prevailing winds often reverse, which *will* have a very pronounced effect on trajectory.

How many here are aware that at longer ranges, 1,000 yards for example, a left wind of even 5 to 10 mph will drive a bullet downward as much as 1 to 2 FEET, and that a right wind of the same value will raise impact?

Not to be argumentative, but, when it comes to this subject of a bullet "beating it's way through rain" theoretically slowing it and making it drop noticeably more, fact and field observation seem to contradict our shared intuition.

I too had "thought" that rain would slow down the bullet as it plowed through an infinite number of raindrops on it's way to the target. I came to see that I had been mistaken, based on both my own experiences and the experiences of other long range shooters. While we, due to the refresh rate of our eyesight, perceive rain to be "streaming" downward, it is actually a series of discrete droplets that may or may not be intersected by any given bullet on it way to the target.

The technical explanation has to do with the forward shock wave displacing any raindrops prior to the bullet's arrival. Erratic flight would then, by necessity, be caused by some other factor, since the bullet *never touches* a raindrop.

Intuitively (again), I would suggest that we cannot get something for nothing, and that a certain amount of forward inertia *must* be sacrificed to "move" the (minuscule) mass represented by raindrops, but, in practice, this minute amount of inertia lost is very small in comparison to the bullet's kinetic energy. So small as to be completely buried in the "noise" and not worth factoring into any trajectory equation.

The obscuring "noise" consists of variations in muzzle velocity, aiming error, trigger control, crosswind, bullet weight and meplat shape.

Just taking muzzle velocity as an isolated example, we have both constant shot to shot variation and an overall reduction in MV upon temperature drop.

So, if we shot yesterday at 85oF and zeroed at 1k, but today (it's raining and) our ambient temps are down 10o, to what do we attribute the extra drop?

Many people shoot loads that exhibit extreme velocity spreads of 25 fps, even 50 fps. Only 25 fps MV with a 175 SMK at .308 velocities (2,600 vs. 2,575 fps) equates to over 8" difference in drop at 1k - actually quite a bit of "noise".

LOL, as minor as it may seem, it has been conclusively proven that uniforming (trimming) meplats provides more consistent long range performance by reducing vertical variations due to bullet shape (BC) differences. The same experts that agree that this step is worth the time, effort and tool costs tend to disregard the effects of rain. Who here trims their long range bullet noses? Not me. . .

I *will* find and post the extensive military study that *proves* that rain's effect on bullet flight is not worthy of consideration in our context.

General Geoff
August 25, 2008, 01:25 PM
The technical explanation has to do with the forward shock wave displacing any raindrops prior to the bullet's arrival. Erratic flight would then, by necessity, be caused by some other factor, since the bullet *never touches* a raindrop.

This is simply incorrect; the shockwave created by a bullet is generated by the tip of the projectile, not some imaginary point in front of it. If a rain drop is in the way, the bullet's going to hit it. The shockwave will not somehow shelter the bullet from the water, any more than a bullet fired into a pool.


Even if the drop of a particular round in heavy rain is negligeable, that doesn't mean that it's displacing the rain with some sort of voodoo precursing shockwave. It just means the few rain drops that it strikes on the way to the target don't have a profound effect on its ballistic path.

30Cal
August 25, 2008, 01:54 PM
From what I've seen, it has no effect, at least until the target becomes heavily obscured.

taliv
August 25, 2008, 03:01 PM
even in a frog-strangler, the odds of hitting a drop would be quite low

EShell
August 25, 2008, 05:06 PM
This is simply incorrect; the shockwave created by a bullet is generated by the tip of the projectile, not some imaginary point in front of it.
If you say so . . . but what I see is not at all imaginary:
http://www.nasa.gov/images/content/185591main_f-516.jpg

Less obvious here, but still barely discernible:
http://www.firearmsid.com/Feature%20Articles/soundofbullets/media/sound1.jpg

Here's another:
http://content.answers.com/main/content/img/McGrawHill/Encyclopedia/images/CE620600FG0010.gif

This is my own favorite:
http://static.photo.net/attachments/bboard/001/001Rmg-4412284.jpg

packnrat
August 25, 2008, 05:15 PM
i hate the rain...

try needed glasses and it starts to rain. very hard to see much of anything.

frend or foe. can not tell....maybe that was just a tree......:scrutiny:


:uhoh:


.

MTMilitiaman
August 25, 2008, 05:26 PM
Anymore, time and opportunity for me to go shooting is so rare that Hades himself couldn't stop me. I'll shoot in the sun, rain, or snow.

BammaYankee
August 25, 2008, 05:33 PM
Taliv raises an excellent point...

Many on this forum talk about what they would do in which situation using this gun and that ammo. Many others talk about shtf, disaster scenarios, etc etc. Well, what if these situations really do come to pass, but it's not 70 degrees, sunny, with no humidity when it comes time to use your gun?

I have competitively shot & hunted in the snow, feezing rain, and the sweltering heat of the deep south and it really does challenge one's shooting ability! No one would say it is fun, but I think it is good experience.

How can anyone on THR seriously discuss or prepare for situations that may require putting one's gunmanship to the test without at least experiencing less than ideal shooting conditions? To me that is down right irresponsible!

Bartkowski
August 25, 2008, 05:36 PM
It seems that EShell has lots of experience and knows many others with similar levels of experience, whereas General Geoff is just saying what he thinks is true. I haven't shot very long distances, but I have shot in the rain and have not noticed any effect.

jjohnson
August 25, 2008, 05:41 PM
Well, I'm not sure I like shooting in foul weather just because I like the weather that way, but:

1) The range definitely empties out in bad weather.;)
2) If other people ARE there, they're the serious shooters, not Mall Ninjas such.
3) Ya know, when you HAVE to shoot, it's probably not going to be in your choice of weather, anyway, so you may as well get in proper training.

Funderb
August 25, 2008, 05:50 PM
the effect is humidity, not rain, humidity greatly affects bullet traj.

Howard Roark
August 25, 2008, 05:55 PM
I've shot high power in the rain several times. 600 and 1000 yards. I had no elevation changes. I did blow a lot of primers due to increased chamber pressure.

EShell
August 25, 2008, 08:58 PM
the effect is humidity, not rain, humidity greatly affects bullet traj
Well, not as much as one might think, and probably opposite what one would *think*.

Of the major environmental factors affecting trajectory; barometric pressure, temperature, altitude and humidity (the combined effects of which accounted for in density altitude), humidity is one aspect actually not worth calculating. When humidity increases, H2O actually displaces heavier/denser atmospheric components and net air density declines. When air density declines, drop is reduced, yet another counterintuitive concept that was traditionally misunderstood even by the US military. The military has since revised doctrine to reflect scientific truth, our goal here.

The reason air seems "thicker" (and assumed more dense) when humidity increases is simply because we are air cooled beings, and we depend on evaporation to cool, which is impeded by excess atmospheric humidity.

If we calculate the drop of a .308/175/2,600 fps at 1,000 yards from a 100 yard zero at, say 10% humidity, we arrive at 39.4 moa (Sierra Infinity). If we change nothing else but increase humidity to, say 95%, and rerun the numbers, we now have only 39.3 moa.

Two things become apparent: First, the scant .1 moa difference in drop is yet another factor buried in the "noise" and so not worth fooling with, and second, increased humidity results in decreased drop . . . go figure.

I realize that this too is not what is expected, but is what happens, and I would again suggest that other unnoticed factors would be responsible for any change in drop that would seem attributable to humidity.

taliv
August 25, 2008, 09:35 PM
not to pick nits in my own thread, but wouldn't that make us water-cooled? ;)

MGD 45
August 25, 2008, 10:10 PM
Well, I have shot my .308 168 gr. BTHP in the rain to collect data for my sniper log book. Of course, on the day it was raining I was only able to shoot out to 100 yards. The rain had no effect what so ever on the bullet dropping. It did however rise up 1/2 an inch in height from POA to POI. However, I contributed this to a drop in Pressure in the atmosphere.

Now, the rain was more like a steady light rain vs. a heavy fat downpour.....

telomerase
August 25, 2008, 10:48 PM
How can anyone on THR seriously discuss or prepare for situations that may require putting one's gunmanship to the test without at least experiencing less than ideal shooting conditions? To me that is down right irresponsible!

Is it more irresponsible than keeping one's children in a country which is involved (via foreign aid) in every conflict in the world (usually on both sides), yet has no civil defense?

Responsibility is un-American, and I for one won't stand for it!

Well, OK... is it all right if I take an umbrella?

boilingleadbath
August 25, 2008, 11:03 PM
The photos you showed of bullets with notably detached bow shocks were scarcely supersonic - if you look at the rifle bullet, you'll notice that the bow shock is pretty much ON the point of the bullet.

Besides, I wouldn't expect those shocks to move the rain very well.

However, that doesn't mean the rain effects the bullet. Let's do some math.

Lets say that:
the rain storm drops one inch of rain in two hours
a raindrop is 1/100th of a ml (pretty small for that type of rain, I'd expect, but we are being cautious here)
those raindrops fall at 25 mph
That those raindrops are infinitely small (makes them hard to hit)
That you are shooting a .3" diameter bullet
At 1000 yards

So, the flight path of the bullet has a volume of 41,000 cm^3
And a cubic centimeter of air contains 2.85*10^-5 raindrops at any given point in time
So the average bullet encounters 1.2 raindrops on it's way to the target... over 1000 yards... in an incredibly dense rainstorm of unusually (?) small raindrops.

I can't find my stats notes righht now, so I can't tell you the probability that the raindrop will hit 0/1/2/... raindrops.

Dr. Tad Hussein Winslow
August 25, 2008, 11:11 PM
Good analysis, Ed - thank you. :)

oldgold
August 25, 2008, 11:21 PM
I ran and shot in a .22 silhouette match for ten years. We had a nice covered shooting building so matches were held regardless of the weather. Many matches were held in the rain. I never noticed any effect the rain had on point of impact. Many of our top scores were posted in a light rain.

Back in the sixties I broke my first 50 straight at trap in a driving snow storm. I was so cold and miserable I was not keeping score in my head. Just wanted to get inside. Shoot, shiver and shut up?

EShell
August 25, 2008, 11:55 PM
not to pick nits in my own thread, but wouldn't that make us water-cooled? :) Good question.
The photos you showed of bullets with notably detached bow shocks were scarcely supersonic - if you look at the rifle bullet, you'll notice that the bow shock is pretty much ON the point of the bullet.
Point taken, but, it sure did appear that we were suddenly dealing with absolutes, and ALL of the pics suggest that the shock wave does precede the bullet, albeit to a greater or lesser extent.

Regarding degrees fo supersonic flight, FWIW, most .308 bullets (an easy to reference and well known set of ballistic data) are near trans-sonic at 1k anyway, and some, like the 168 SMK, often go completely subsonic even before 800, depending upon density altitude. Of course, as soon as we go trans-sonic, the front shock wave collapses and the rear shock wave and turbulence overtake the bullet.
Besides, I wouldn't expect those shocks to move the rain very well."Move" or "vaporize"? All we need to do to negate influence is to reduce density to something less than "water". The reason I would suggest "vaporize" is that the bullet trace is often quite evident on rainy days, resembling smoke . . . or vapor. Simple displacement would cause no appreciable change in trace, which is often visible even on a sunny day.
So the average bullet encounters 1.2 raindrops on it's way to the target... over 1000 yards... in an incredibly dense rainstorm of unusually (?) small raindrops.I defer to your statistical analysis, but will maintain/agree that rain has very little to no effect on bullet flight, my original premise.

Hoplophile
August 26, 2008, 12:14 AM
"Never really did much target shooting in the rain, but I've sat in my share of tree stands during downpours. Deer usually bed down when there's a frog-strangler, but when the rain stops it is good to be on the stand. I usually try to sit it out unless there's no end in sight. I usually carry one of those plastic rifle bags for my gun in case it starts raining. What do you guys do about rust?"


...Wow, someone used the term "frog-strangler". Thought I was the only one.

wanderinwalker
August 26, 2008, 12:27 AM
My first season of competitive Highpower shooting, we shot a match in the mid-40s-low-50s and drizzle/rain, in May. Gotta love New England weather! :evil: Actually, I didn't think there was any other way to shoot a Highpower match by the time we were through the spring and early summer that year. It just didn't seem right if my AR wasn't spitting water on my with every round! :p

Honestly, I've never noticed enough POI/POA shift in rain or snow to worry me, especially out to ranges you can still see a target.

Actually, back to my first HP season, I used to practice in February when I had to shovel out a firing point through the snow drifts. If you can shoot well at 20 degrees, fingers and toes out of contact, in blowing snow, rain in July is easy.

I have also fired many rounds of 9mm down into the single-digits, and can assure you that ammo just barely powerful enough to cycle at 60-70 degrees, will likely give you some issues at those temperatures. Boost things into a more normal spec, and you'll be fine.

taliv
August 26, 2008, 12:31 AM
oddly enough, almost all of my HP shooting has been in 90* or higher sun. i can only remember shooting one rapid fire string in the rain.

i can't imagine shooting HP in the snow.

boilingleadbath
August 26, 2008, 03:38 PM
"'Move' or 'Vaporize'"

I'm not sure it's consequential - ultimately, even if the bow shock breaks up the raindrop, the mass is still there, and has to be moved.

I don't know enough about the situation to be able to tell if moving that mass is:

1) Even possible through purely shockwave effects deflect the rain
1B) Going to produce unbalanced loads on the bullet even if it is.

#1 is a complete unknown to me. I'm kindof doubting it, given how THIN shockwaves generally are, but I have no formal or informal training in the matter.

As for as #1B goes - it certainly possible that the shock redirects the "increased density zone" that was formerly the raindrop without communicating any (as much) force to the bullet... but again, I know very little about shocks.

******

I'm not doubting your conclusion that rain doesn't affect bullet flight to any appreciable degree.

******

Anyways, lets look at a more-or-less worse-case scenario, were the raindrops aren't influenced by the shock at all. How much will the rain deflect the bullet?

Bullet is assumed to be 10 grams, 2500 fps, with a conical front .6" long and .3" in diameter, and it hits a .01 gram raindrop.

Again, I have no formal fluid dynamics training, so I'm just doing calculations which seem reasonable to me.

Let's assume that when the bullet impinges on the water, the force is normal to the face of the bullet. Further, let's ignore the deflection of the water drop and bullet. So they are both essentially frictionless points/surfaces.

The inverse tangent of the angle perpendicular to that of the bullet's cone is 4. So I think the raindrop will acquire 4 times as much sideways movement as forwards movement.
And the raindrop has to acquire a sideways velocity equal to 1/4th of it's relative velocity.

If I did my physics right...
For the raindrop:
deltaV.radial = 606 fps
deltaV.axial = 75 fps

Of course, divide by 1000 because of the weight difference, and you get .6 and .075 fps change to the bullet's velocity.

Which, even compounded over the 1.5 second flight time, isn't very significant. (though I'm sure it is an inaccurate idea to ignore the other aspects that result from bumping a bullet.)

EShell
August 27, 2008, 12:11 AM
#1 is a complete unknown to me. I'm kindof doubting it, given how THIN shockwaves generally are, but I have no formal or informal training in the matter.
The full dynamic is unknown to me as well, but, as thin as a supersonic shockwave may be, it can have a certain impact that is more obvious when scaled up enough to see ( ;) ):
http://en.wikibooks.org/wiki/Image:F-14_Tomcat_sonic_boom.ogg

innerpiece
September 18, 2008, 06:13 PM
EShell, thanks for the excellent contributions.

ip.

Floppy_D
September 18, 2008, 06:35 PM
I played some great 5-stand and sporting clays last weekend, in a pretty good rain. You're right, it was rather nice. The wind came from our backs (so our faces didn't get soaked.) It was a nice change of pace.

45B@cav
September 18, 2008, 08:31 PM
My first 40 out of 40 was shot in the rain on pop up targets. I love it.

Grump
September 19, 2008, 04:50 PM
some, like the 168 SMK, often go completely subsonic even before 800

Re-run your ballistics. What altitude are you talking here? At 600 ASL, 85F and all that, a 168 at "only" 2550 MV (which about equals 2600 at 78 feet military measurement) is going 1250 fps at 800 yards.

1079 at 1,000 yards.

Actual speed of sound 1142 fps (that's where the higher-altitude conditions shine!), so it's subsonic between 900 and 950 yards.

Now, if you define transonic as between mach .8 and 1.2, then you're *starting* to get excess wind drift, etc. at 1370 fps at that altitude, which is even closer, at 700 yards.

My 3100-foot firing point lets me shoot 168s at 2600 and they're still supersonic--1158 fps--at 1000 yards, actual speed of sound is 1114 fps, and I've been transonic (less than 1336 fps) from slightly more than 830 yards out. 170 more yards to go transonic with a bullet that's still spinning at almost its original RPM (spin decays almost negligibly compared to velocity).

Handgun Silhouette shooters have been getting decent accuracy for decades with loads that transected those velocities, but were shot at targets no more than 200 meters away. They have only noted more wind drift than with super-heavy bullets going slower...

Flat-base 150gr .30 Caliber M2 bullets, on the other hand, are starting to scatter quite a bit at 600 yards. The guy I pulled targets for one day made it hard to know when he shot, as they were fully subsonic at that distance and they were NOT in the middle. If he were a better shot with a better rifle (rack-grade M1 Garand...), I could estimate the accuracy disadvantage. But he was having a bad day with a sorta bad rifle and USGI Ball ammo. Not good.

BeltfedMG
September 19, 2008, 05:06 PM
If nothin else theres alot of good info on here.

Owen
September 19, 2008, 05:11 PM
The shock wave that is pushed ahead of the bullet displaces raindrops and there is no appreciable loss of velocity or increase in drop.


Are you sure? Sources? The tip of the bullet and the shockwave share the same space. In addition, the bullet is going so fast the rain is relatively stationary., so the bullet and the shackwave would be hitting the rain drop at the same time.

(trying to figure out how to film this phenomonon)

Owen
September 19, 2008, 05:21 PM
ok read the rest of the thread.

the problem with looking at 800 yds is that the bullet is already there. you could put s thin sheet of steel just in front of the target, and it won't change POI very much. the problem is back a 100 yds, where little changes make a big difference down range. At 2700fps, the shock wave of a rifle bullet is pretty much on the tip.

I know that rain doesn't have much affect on trajectory, even at long range, i just don't buy your explanation. BTW, I call foul on the transonic pistol bullet pic you used.

Eyesac
September 19, 2008, 06:03 PM
rangerruck that'a great story!

1858
September 19, 2008, 08:51 PM
"Move" or "vaporize"? All we need to do to negate influence is to reduce density to something less than "water". The reason I would suggest "vaporize" is that the bullet trace is often quite evident on rainy days, resembling smoke . . . or vapor. Simple displacement would cause no appreciable change in trace, which is often visible even on a sunny day.

Isn't the "trace" that you see actually condensation due to water vapor in the air condensing in the low pressure region behind the bullet? :confused:

:)

EShell
September 23, 2008, 01:41 AM
Re-run your ballistics. What altitude are you talking here? At 600 ASL, 85F and all that, a 168 at "only" 2550 MV (which about equals 2600 at 78 feet military measurement) is going 1250 fps at 800 yards.

1079 at 1,000 yards.

Actual speed of sound 1142 fps (that's where the higher-altitude conditions shine!), so it's subsonic between 900 and 950 yards.

Now, if you define transonic as between mach .8 and 1.2, then you're *starting* to get excess wind drift, etc. at 1370 fps at that altitude, which is even closer, at 700 yards.
Grump, you're right about this, and more properly I should have said trans-sonic, which is really the case, where the 168 SMK often loses stability. Working at rifle classes at Quantico (physical altitude @ 400'ASL/density altitude often seen in negative numbers), we tell the student they'll need 175s for long range. They don't believe it, since they get such good results with 168s at closer ranges and/or higher altitudes, and show up with 168s anyway. We see sideways bullets on steel and through the backers in the pits at the first sign of instability, often by 800 yards, and then, if they keep trying as we move back to 1k, bullets are all over the berm and keeping them on the 6x6 backer is not possible.My 3100-foot firing point lets me shoot 168s at 2600 and they're still supersonic--1158 fps--at 1000 yards, actual speed of sound is 1114 fps, and I've been transonic (less than 1336 fps) from slightly more than 830 yards out. 170 more yards to go transonic with a bullet that's still spinning at almost its original RPM (spin decays almost negligibly compared to velocity).I shoot the Allegheny Sniper Challenge at Seneca Rocks WV twice yearly, and the match director lives in that area. He shoots a 20" LTR with 168s almost exclusively, and regularly makes hits on targets beyond 1k. the physical altitude is above 3,500 ' ASL, and DA often exceeds 6,000'.Handgun Silhouette shooters have been getting decent accuracy for decades with loads that transected those velocities, but were shot at targets no more than 200 meters away. They have only noted more wind drift than with super-heavy bullets going slower...True, but not only were the ranges short, as you point out, but certain bullet shapes do not care nearly as much as they go trans-sonic, and being overtaken by the turbulence doesn't have the same effect.Flat-base 150gr .30 Caliber M2 bullets, on the other hand, are starting to scatter quite a bit at 600 yards. The guy I pulled targets for one day made it hard to know when he shot, as they were fully subsonic at that distance and they were NOT in the middle. If he were a better shot with a better rifle (rack-grade M1 Garand...), I could estimate the accuracy disadvantage. But he was having a bad day with a sorta bad rifle and USGI Ball ammo. Not good.Yes, subsonic arrival is a PIA to spot. I have taken to watching the berm for both the presence and locations of hits when working the pits. I've seen bullets kick up dirt one position over, and have them call me for a spot.

ok read the rest of the thread.

the problem with looking at 800 yds is that the bullet is already there. you could put s thin sheet of steel just in front of the target, and it won't change POI very much. the problem is back a 100 yds, where little changes make a big difference down range. At 2700fps, the shock wave of a rifle bullet is pretty much on the tip."Pretty much", yes, but still somewhat ahead, with a layer of compressed air between the bullet tip and the primary nose shockwave. As velocity slows, this distance between the shock wave and bullet point increases, and as we go transsonic/subsonic, it get WAY ahead of the bullet, but, I see below that you don't like transsonic subsonic pics.I know that rain doesn't have much affect on trajectory, even at long range, i just don't buy your explanation.OK, that's reasonable, but there is quite a bit of data to suggest that it is correct to think that the preceding shock wave might have the tendency to displace or vaporize any droplets prior to the bullets arrival. In this case, "prior" is "prior" and if the droplet is displaced, the bullet never touches it. The example given with the jet, traveling beyond the speed of sound certainly "displaces" a lot of water with it's bow wave.

BTW, I call foul on the transonic pistol bullet pic you used.Why, whatever for? That pic was among several posted in direct response to the unequivocal absolute statement that the shock wave was invariably behind the bullet, which it clearly is not, even in the super sonic pictures you seem to prefer.

Certain components of shock/compression and turbulence will often be behind the bullet, and farther behind as we get faster, but, it would certainly seem that the bow compression wave, our subject of discussion, is always out front.
Isn't the "trace" that you see actually condensation due to water vapor in the air condensing in the low pressure region behind the bullet?Trace is air pressure/density variations around the bullet vs light refraction. Trace is evident even in very low humidity atmosphere and I've never noticed it change visibility under varying humidity conditions, but certain light conditions make it quite visible.

m4joey94
February 4, 2009, 08:02 PM
yea shooting in the rain is alot better, ESPECIALLY SINCE NO ONE'S LEFT ON THE RANGE :D!!! and it helps your shooting skill a lot, gotta have more concentration and stuff.

shaggy430
February 4, 2009, 11:26 PM
Nowadays the only time I like to go to the range is when it is raining. The benches are covered, but it still keeps all the yahoo's who just bought their brand new AR's and Glocks since the election away. Most have no clue about gun safety. Not that I have anything against Glocks and AR's, just the idiots who 6 months ago had never touched a gun but now think they are Rambo. Last time I went to the range on a sunny day there was an accidental discharge while everyone was down range. :cuss:

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