Ballistics over water at long range

shooting over a body of water will affect the trajectory depending on the temp of the water and the size of the body of the water. Everything affects trajectory. Shooting on one side of the world as oposed to the other other side changes trajetory too, depending on gravitational pull. shooting near the equator or far from the equator again affects the trajectory of the bullet. Everything affects the trajectory, just how much is anyones quess. the science is astounding once you study it. Your question has an answer just no definite mathamatical calculation can help you determine how much you little trajectory will be affected.
 
Shooting over water won't *directly* affect the bullet's trajectory (either its vertical drop or its horizontal drift).

There might be indirect effects:

* If the water is cooler than the land, and the air over the water is cooler than the air over the land, you will be shooting through cooler air over the water. *This* (the cooler, denser air) will affect your bullet - it will drop a bit more. Plug some figures into a ballistics program to see what you're dealihng with (for example, 5 degrees C cooler, shooting at 1,000 yards).

* if the air over the water is more humid, that will affect the density of the air. Air of a given temperature that is more humid, is less dense.

* if the winds over the water are stronger than the winds over a sheltered piece of land, that will affect the bullet (mostly horizontal effects, though sometimes there are smaller vertical effects too).

* water tends to be more uniform (flat, level) than most land, except perhaps the Prairies. Generally this will make for fairly consistent conditions. Also, there tend to be fewer thermals (rising or descending columns or bubbles of air) over water than over most land masses.
 
Shooting over water won't *directly* affect the bullet's trajectory (either its vertical drop or its horizontal drift).

There might be indirect effects:

* If the water is cooler than the land, and the air over the water is cooler than the air over the land, you will be shooting through cooler air over the water. *This* (the cooler, denser air) will affect your bullet - it will drop a bit more. Plug some figures into a ballistics program to see what you're dealihng with (for example, 5 degrees C cooler, shooting at 1,000 yards).

* if the air over the water is more humid, that will affect the density of the air. Air of a given temperature that is more humid, is less dense.

* if the winds over the water are stronger than the winds over a sheltered piece of land, that will affect the bullet (mostly horizontal effects, though sometimes there are smaller vertical effects too).

* water tends to be more uniform (flat, level) than most land, except perhaps the Prairies. Generally this will make for fairly consistent conditions. Also, there tend to be fewer thermals (rising or descending columns or bubbles of air) over water than over most land masses.

How about "thermoclines" which can be either an updraft or a downdraft ?
These will certainly affect the trajectory of a bullet just as they do to aircraft.
 
This effect also happens in golf. Hitting over a body of water can effect the flight of the golf ball. More so the effect is observed in distance deviation, rather than lateral deviation. As a golf shot is inherantly less accurate than a bullet, and would be damn hard to quantify lateral deviation from this effect. But distance, for sure there is an observable effect.
 
I think shooting over ice would be a great idea. Flat, level, open - pretty much ideal for a rifle range. Easy to put up a few streamers as wind flags if you want (a coat hanger and a strip of plastic surveyor's tape). Use a snowmobile or ATV to run back and forth to the target in no time flat. Set up targets at a variety of distances. Practice with a laser rangefinder and setting up first-shot elevations.
 
Might not be illegal but is certainly not recommended - Bullets will "skip" once they hit the water (like skipping a small rock) and can tend to go in all directions. Also - how would you control the "traffic" - what if some one were to paddle a boat across etc.
However in your case it looks like your bullets will not hit the water since the target is still 200 m inland
 
How about "thermoclines" which can be either an updraft or a downdraft ?
These will certainly affect the trajectory of a bullet just as they do to aircraft.

Updraft? downdraft? Thermoclines exist in water only. they are usually very stable, as the second they become unstable, mixing occurs and there really isn't a thermocline left.

large convective currents or tides could change surface temperature in isolated areas of a lake enough to affect air density...

never shot distance over water, so would be interested to see these effects in person.
 
Updraft? downdraft? Thermoclines exist in water only. they are usually very stable, as the second they become unstable, mixing occurs and there really isn't a thermocline left.

large convective currents or tides could change surface temperature in isolated areas of a lake enough to affect air density...

never shot distance over water, so would be interested to see these effects in person.

http://en.wikipedia.org/wiki/Thermocline#Atmosphere

I am sure there are other technical terms that are applied to the air rising or or moving differently above a body of water or ice. I am not an expert on the terminology of what air does, but from experience know that shooting over larger bodies of water or ponds of ice make a bullet do weird things.
My range has a deep dug out in the middle of the field and shooting over the dugout is ALOT different than shooting over land. Also with filming the shots I have found there to be differences when shooting over the land with crop still in early growth versus fully grown and awaiting harvest ( wheat or barley crop) A meteorologist friend has suggested ( no science to back it up just a possibility) that the crop generates or collects heat which may be effecting the air temp and humidity in the areas where crop is versus where crop isn't.

If you get a chance to fly in a hang glider or non powered glider you will find that when flying over either water or crop where there are defined differences between either land and water or crop and barren land the craft will be slightly effected. Either with an updraft or a down draft.
I believe they call these thermals, which I believe is short for thermalcline ??
 
yes thermals , but they are convection currents, a thermocline is a basically broken down into "Thermo" (temp) and Cline (line or division). Radiant energy from the sun hits the feilds, and heats air which then rises. can be a pretty fun ride in a small aircraft on the right day. you can see it on the right day with the right amount of humidity, etc. if you're ever in the Squamish Valley in summer you can see this effect on Diamond Head Mtn, the convection currents (updraft in this case) will start to generate large cumulous clouds over the peak of the mountain, from the warmer, moist air from below riding up on these currents into the colder, denser air above.

again, never shot over water or ice any more then 300m or so, hopefully get a chance to see some of this in effect one day. it's to bad there is no way to track the flightpath of a bullet....

just daydreaming, but your dug out would prolly account for denser air by being a low spot and the general cooling effect of cooler moist earth?
 
it's to bad there is no way to track the flightpath of a bullet....

just daydreaming, but your dug out would prolly account for denser air by being a low spot and the general cooling effect of cooler moist earth?

There are short times when the water temperature is higher than the air temp.

With a high def video camera that I mount behind my spotting scope I have video of bullets in flight. It is interesting to say the least how a bullet actually does fly.
 
Well I'm getting excited to try this. I also have video'd my little .243 bullets flight paths through my basic sony digital video camera. Shows quite well how the wind pushes it around.

Its getting too late to find a perfect spot for shooting across the lake, it will be frozen soon. Thats next years project. I will just shoot down the frozen lake in a safe spot this winter and like the previous poster said setup targets at multiple ranges.

Good info in here though!


BTW rick if you have any short video clips of your big boomer bullets on video I'd love to see it. Especially through a hidef camera and spotting scope. Actually I'm sure all of would like to see it.
 
Well I'm getting excited to try this. I also have video'd my little .243 bullets flight paths through my basic sony digital video camera. Shows quite well how the wind pushes it around.

Its getting too late to find a perfect spot for shooting across the lake, it will be frozen soon. Thats next years project. I will just shoot down the frozen lake in a safe spot this winter and like the previous poster said setup targets at multiple ranges.

Good info in here though!


BTW rick if you have any short video clips of your big boomer bullets on video I'd love to see it. Especially through a hidef camera and spotting scope. Actually I'm sure all of would like to see it.


The still photo is where we shoot these from, the distance 1075 yards to the gongs and tanks. The particular time that we shot the videos, we were pointed slightly to the left so that the bullets were landing in the crop in the background.

IMG_2535.jpg




This video was taken shooting in the opposite direction than the 1st, distance is only 1000 yards, but there is still the gully and creek to get bullets ovr which can make for some interesting corrections.



In this video clip if you look carefully on the right side of the reticle you can see the bullets contrail just as it comes into frame before hitting the target.


I need to dig through the rest of my videos to find some of the 1s we have shooting over the dug out in the spring and also in winter.
 
Well, I used to shoot over water all the time when I was young and dumb until I got crap from a pair of Mounties for doing so.

The part I remember from what they were telling me was that is unlawful to fire a "single projectile firearm" over a body of water.

I am not sure where you will find it whether it will be the Firearms Act, Criminal Code or the Migratory Bird act. You would have to look it up.

Besides the fact, shooting over a surface that will ricochet is an unnecessary risk.

You won't find it as there is no such regulation... Have you ever shot over a rock? Shooting over and at are two different things.
 
The biggest problem shooting over water is the ability to judge distance accurately.
Thermals can vary considerably but are they any different than shooting over a valley?
The variations in all situations are just that - variable. The time it would take to write the book on shooting over water might just be more than we have.
 
Here are some pics of "The Outpost of The Empire" range.
As you can clearly see, the little white target across the river is in fact over the water, as are the other targets that are set closer.
I shoot at 1K, 700 yards, 410 yards and one mile over the water, and lthougbh I'm sure the water affects the conditions, I simply shoot to the conditions present, I don't try to analyse them, it would burn up what grey matter I have left!:rolleyes:
settingupforthe1K.jpg

Cat
 
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