Not sure when shooting over water say at 1200 or 1300 yds will it have an effect on poi, any thoughts on how it will be effected.
shooting over water
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Re: shooting over water
changes in temp, also wind are some. Last but not least how close the the water will the projectile be? Can be a bit dangerous.
changes in temp, also wind are some. Last but not least how close the the water will the projectile be? Can be a bit dangerous.
Re: shooting over water
Nothing dangerous, I'm shooting over it and not into it. Bullet path is probbaly about 7 to 8 feet at the end of the barrel to a target that is 1250 yds away that is about 25feet above the water. So the bullet path is looping over the water. Reason why i am asking, I had a friend that had a friend of a friend thought that it would have a diffrent air dens. and that it would effect the flight.
Nothing dangerous, I'm shooting over it and not into it. Bullet path is probbaly about 7 to 8 feet at the end of the barrel to a target that is 1250 yds away that is about 25feet above the water. So the bullet path is looping over the water. Reason why i am asking, I had a friend that had a friend of a friend thought that it would have a diffrent air dens. and that it would effect the flight.
Re: shooting over water
If your soooting 1200 yrds over cold water your POI should be lower than 1200 yrds over heated land because of thermal lift but not much. I think? maby someone that realy knows will chime in. I have asked this on the Hide before but never got a real definitive answer.
If your soooting 1200 yrds over cold water your POI should be lower than 1200 yrds over heated land because of thermal lift but not much. I think? maby someone that realy knows will chime in. I have asked this on the Hide before but never got a real definitive answer.
Re: shooting over water
Just kinda wondering, the lakes i'm shooting over are not deep so right now during 90 degree days the water temp prob. 80-82. I shot this afternoon at this target 1257yds, land to water 250yds,over water for about 400yds, then over land for 300yds, back over 2nd pond for 200yds, and last 100yds over land into target. I know Its not ideal but to me if I shoot at further distances it will only help my shooting
I also think ideal is boring
Just kinda wondering, the lakes i'm shooting over are not deep so right now during 90 degree days the water temp prob. 80-82. I shot this afternoon at this target 1257yds, land to water 250yds,over water for about 400yds, then over land for 300yds, back over 2nd pond for 200yds, and last 100yds over land into target. I know Its not ideal but to me if I shoot at further distances it will only help my shooting
I also think ideal is boring
Re: shooting over water
Air density is affected by temperature. If the temperature of the water is significantly cooler than the air temperature over land, you might get a slight increase in local air density. However, on a shot at that distance, the bullet is going to be in the air high enough that it's unlikely to have much effect.
If there's nothing to hit in the water, and no safety issues from a bounce off the water, I wouldn't be very concerned.
If you wanted to calculate the worst case condition, measure the water temperature. Then do two calculations with a ballistic program, one with the air temperature the same as the water temperature, and one with the air temperature over land. See how much difference you get.
Air density is affected by temperature. If the temperature of the water is significantly cooler than the air temperature over land, you might get a slight increase in local air density. However, on a shot at that distance, the bullet is going to be in the air high enough that it's unlikely to have much effect.
If there's nothing to hit in the water, and no safety issues from a bounce off the water, I wouldn't be very concerned.
If you wanted to calculate the worst case condition, measure the water temperature. Then do two calculations with a ballistic program, one with the air temperature the same as the water temperature, and one with the air temperature over land. See how much difference you get.
Re: shooting over water
Thanks Lindy
My 1st shot came in a little warm 2.25 moa high, I did not think about it untill a little while ago that my ammo baked in the sun for a few hours and was prob. shooting 80 -100fps faster than I had it punched in for. Over all a great time at burning up powder with a new friend thats gtg
Thanks
Brandon
Thanks Lindy
My 1st shot came in a little warm 2.25 moa high, I did not think about it untill a little while ago that my ammo baked in the sun for a few hours and was prob. shooting 80 -100fps faster than I had it punched in for. Over all a great time at burning up powder with a new friend thats gtg
Thanks
Brandon
Re: shooting over water
The only thing that I was taught was that range estimation was more difficult going over a body of water. Targets "appear" farther away and often times people gave a "long" range estimate. I didn't put too much stock in that particular theory and proceeded to use my mil dots to accurately range targets, as did my partner.
It was never mentioned that exterior ballistics would be affected.
This was from a US Army Sniper School train up that never materialized into "real" Sniper School. Sort of a half-assed attempt by a Mech Div to implement snipers into the battlefield without spending any money on "legs" by sending them to Benning.
The only thing that I was taught was that range estimation was more difficult going over a body of water. Targets "appear" farther away and often times people gave a "long" range estimate. I didn't put too much stock in that particular theory and proceeded to use my mil dots to accurately range targets, as did my partner.
It was never mentioned that exterior ballistics would be affected.
This was from a US Army Sniper School train up that never materialized into "real" Sniper School. Sort of a half-assed attempt by a Mech Div to implement snipers into the battlefield without spending any money on "legs" by sending them to Benning.
Re: shooting over water
If it's anything like golf your bullet will never make it, it will always go in the water....
If it's anything like golf your bullet will never make it, it will always go in the water....
Re: shooting over water
At 1200-1300yd, a discrepancy of 2.25MOA is nearly negligible. IMHO, it falls within the expected dispersion at such distances.
On might reasonably expect relative humidity over the water to be elevated, resulting in decreased overall air column density, decreasing flight duration and contributing to a slightly higher POI. I'm assuming that the over-water passage constitutes a significant portion of the trajectory.
One can also expect significant water surface area to contribute to thermal column activity, with consequent horizontal airflow patterns. The more sunlight is present, and has been present, the more pronounced this effect becomes. Water and land absorb and radiate solar thermal energy differently, resulting in vertical airflows. Between their epicenters, air flows horizontally to maintain pressure equilibrium, but the temperatures of the ascending and descending columns results in air density variance. These variances alter flight times, and consequently result in vertical displacements of the POI.
While humidity is usually written off, increased distances multiply minor effects, and the thermal activity could be reasonably expected to have a more significant effect than the humidity.
Greg
At 1200-1300yd, a discrepancy of 2.25MOA is nearly negligible. IMHO, it falls within the expected dispersion at such distances.
On might reasonably expect relative humidity over the water to be elevated, resulting in decreased overall air column density, decreasing flight duration and contributing to a slightly higher POI. I'm assuming that the over-water passage constitutes a significant portion of the trajectory.
One can also expect significant water surface area to contribute to thermal column activity, with consequent horizontal airflow patterns. The more sunlight is present, and has been present, the more pronounced this effect becomes. Water and land absorb and radiate solar thermal energy differently, resulting in vertical airflows. Between their epicenters, air flows horizontally to maintain pressure equilibrium, but the temperatures of the ascending and descending columns results in air density variance. These variances alter flight times, and consequently result in vertical displacements of the POI.
While humidity is usually written off, increased distances multiply minor effects, and the thermal activity could be reasonably expected to have a more significant effect than the humidity.
Greg
Re: shooting over water
Air temps and density over water are slightly lower and higher.
But honestly it doesn't even majorly effect a wind-glider with a 40' wingspan..
The thermals(waves of heat) coming up off of the desert floor would be more of an anoyance. Messing with exactly where on the target your looking at.
Air temps and density over water are slightly lower and higher.
But honestly it doesn't even majorly effect a wind-glider with a 40' wingspan..
The thermals(waves of heat) coming up off of the desert floor would be more of an anoyance. Messing with exactly where on the target your looking at.
Re: shooting over water
Targets should appear closer when estimating over water, not further due to not having a visual reference to compare size and looking over flat surface. So just with visual estimation your round would fall short due to improper estimate. I didnt see where anyone provided a size of the body of water. The biggest problem I see is range est, and if you where shooting over a large river from bank to bank with high sides. That could cause wind to speed up as if passing between buildings. This also (depending on terrain) may be hard to see and read wind or have a vertical mirage where the speed could not be estimated properly causing a miss. I doubt you would have to worry about arial density (shouldnt be enough of a change from FFP to target) and humidity should be really close to being the same.
Targets should appear closer when estimating over water, not further due to not having a visual reference to compare size and looking over flat surface. So just with visual estimation your round would fall short due to improper estimate. I didnt see where anyone provided a size of the body of water. The biggest problem I see is range est, and if you where shooting over a large river from bank to bank with high sides. That could cause wind to speed up as if passing between buildings. This also (depending on terrain) may be hard to see and read wind or have a vertical mirage where the speed could not be estimated properly causing a miss. I doubt you would have to worry about arial density (shouldnt be enough of a change from FFP to target) and humidity should be really close to being the same.
