I found a place to shoot at 1800 yards. At about half the distance there is about 400 yards of water, maybe 100 yards below the flight path. The thermals are crazy. When the sun is on the water, thermals are going up. When the sun is not on the water the thermals are going down. This prevents me from seeing mirage at the target. I can still see vegetation at target. Any idea how to allow for thermals?
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Shooting over water
- Thread starter Morrigan
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Deleted member 113831
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It likely isn't thermals that are screwing with you. It is likely light refraction off the water.
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Deleted member 113831
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Notice that I didn't say thermals didn't exist. But wind requires velocity to move a bullet. How much velocity do you figure those little thermals have?
It seems like 3 to 4 last time I was there, but Up and Down are not familiar winds for me. Do you think that would push/pull a bullet?
Edit: Eduardo told me that when he was shooting 2 mile with the 460 Steyr, thermals were rising on a hillside and pushing his bullet.
Edit: Eduardo told me that when he was shooting 2 mile with the 460 Steyr, thermals were rising on a hillside and pushing his bullet.
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Thermals and up drafts are definitely a force to be reckoned with and may vary well go hand in hand with light refraction in the case you're seeing, large body of water can do some crazy things to our perspective. From the thermal standpoint, skydiving and being under canopy while gliding over different surfaces, has giving me an incredible appreciation for up drafts, especially regarding the potential influences on ELR trajectories. Just like winds, it's kind of that balance of intensity and duration of force. I've found that understanding fluid mechanics in relation to the terrain at hand is huge part of being successful. The two roads to achieving success, mainly stem from focusing efforts on being very familiar with one specific area or diversifying that exposure across a variety of terrain and conditions.
The later method is what I chose for Ko2M in 2018, where my team placed two shooters in the top 10, even though I had never been on that range before. If I remember correctly day one and two had some significant up drafts, that took a lot of "experienced" shooters by surprise. I don't mean to discredit them but only to pause on what that experience actually is, example David Tubb would probably take my lunch money every day of the week on a high-power range but come to arid high mountain terrain, I feel right at home. My point is its easy to become very confidant in a particular location given enough time but when you take that experience and attempt to apply that data of limited diversity to a different problem, its no longer predictive to the same degree.
The later method is what I chose for Ko2M in 2018, where my team placed two shooters in the top 10, even though I had never been on that range before. If I remember correctly day one and two had some significant up drafts, that took a lot of "experienced" shooters by surprise. I don't mean to discredit them but only to pause on what that experience actually is, example David Tubb would probably take my lunch money every day of the week on a high-power range but come to arid high mountain terrain, I feel right at home. My point is its easy to become very confidant in a particular location given enough time but when you take that experience and attempt to apply that data of limited diversity to a different problem, its no longer predictive to the same degree.
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Deleted member 113831
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A 3 to 4 mph wind would definitely need to be accounted for, regardless of direction or cause.
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So, what your saying is that this is something that I should input a "Try Dope" and note the result in my data book?
So, what your saying is that this is something that I should input a "Try Dope" and note the result in my data book?
What is the ES of the load you are using
Thermal going up a hillside like they see in Raton is far different from what you see over normal terrain, also you have the mirage, snells law effect that has to be factored in.
Heat rising can be an issue, but it also depends on a lot of other factors like MV and where in the flight path the thermals take place
Raton is at 6000ft above sea level, it's high desert and very hot, on top of that, the targets are actually sitting on a cliff face. After 10AM Raton is very hard to shoot and you will see crazy variations.
But none of that means it translates to every location and situation.
In Alaska because of the cold we see the opposite but the results are the same. We have super cold mornings with crisp clean air, that has the cold air sitting on the ground. Once the sun moves to a specific point on the range, we start hitting .5 mils high at 1000 yards, almost immediately after hitting dead on. It lasts about 45 minutes and goes back to normal. It's Snell's Law in Effect.
At ELR Distances, your vertical spread has a lot of bearing on the shots, more so than thermals
Thermal going up a hillside like they see in Raton is far different from what you see over normal terrain, also you have the mirage, snells law effect that has to be factored in.
Heat rising can be an issue, but it also depends on a lot of other factors like MV and where in the flight path the thermals take place
Raton is at 6000ft above sea level, it's high desert and very hot, on top of that, the targets are actually sitting on a cliff face. After 10AM Raton is very hard to shoot and you will see crazy variations.
But none of that means it translates to every location and situation.
In Alaska because of the cold we see the opposite but the results are the same. We have super cold mornings with crisp clean air, that has the cold air sitting on the ground. Once the sun moves to a specific point on the range, we start hitting .5 mils high at 1000 yards, almost immediately after hitting dead on. It lasts about 45 minutes and goes back to normal. It's Snell's Law in Effect.
At ELR Distances, your vertical spread has a lot of bearing on the shots, more so than thermals
Could it be a temperature gradient over the water. Cool moist dense air over the water. Ive seen it shooting across water myself. Pressure might be a part of the equation also.
Xdeano
Xdeano
For sure,
it can be a combination of factor, not just thermal, but inverted air which causes light issues too
looking through cool air vs warm air,
It's part of the reason for Ghost Ships, floating over the water, Fate Morgana
They look that way because the air is inverted,
it can be a combination of factor, not just thermal, but inverted air which causes light issues too
looking through cool air vs warm air,
It's part of the reason for Ghost Ships, floating over the water, Fate Morgana
They look that way because the air is inverted,
My ES is 9. My elevation is 720 at the firing point, 625 ish over the water and 720 ish at the impact area.
That is not the issue,
but at the end of the day you'll never be able to account for it beyond experience and noting what you see giving the various days
you'll just have to manually record the data and hope you can see the similar conditions
but there is no formula for it and you can't see it, you can only look at the conditions based on prior outing and guess it will rise or lower your impact
but it's probably a combination of factors and not just one
but at the end of the day you'll never be able to account for it beyond experience and noting what you see giving the various days
you'll just have to manually record the data and hope you can see the similar conditions
but there is no formula for it and you can't see it, you can only look at the conditions based on prior outing and guess it will rise or lower your impact
but it's probably a combination of factors and not just one
how are you resolving .1 at 1800 ?
What size groups are seeing at 1800, bigger than .2 I suspect
is that all you are worrying about, as I am sure your target is more than .2 tall, I would suspect more than .3
why would you split hairs about .1 ?
If you were seeing .5 Mils than you have a worry
What size groups are seeing at 1800, bigger than .2 I suspect
is that all you are worrying about, as I am sure your target is more than .2 tall, I would suspect more than .3
why would you split hairs about .1 ?
If you were seeing .5 Mils than you have a worry
You are right. the .1 up or down would only be 1.8 mils. But if I account... Say 3 mph up/down it would be 5.2 mils.
I am using 21.1 mils of elevation at 1 mile. I haven't attempted this shot at 1800 yet. Lot's of vegetation and i will likely have to go to the target to find my impacts.
I am using 21.1 mils of elevation at 1 mile. I haven't attempted this shot at 1800 yet. Lot's of vegetation and i will likely have to go to the target to find my impacts.
So you are looking for try dope at 1800 vs your 21.1 mils at 1760
is that what you are looking for, what the difference between 1760 and 1800 would be ?
I thought you had it already shot it and wanted to know why you are seeing variations from day to day ?
If you know your 1 Mile dope, go to a place like JBM put in your data and match it to 21.1 at 1760 then do it with 1800 it should be super close within the plate size.
I would at least use .3 more potentially .5 as your load does not appear very fast, that is more elevation than my 6.5CM at 1780 here in CO
We use around 19.8 mils at 1760 and that translate to roughly 20.5 at 1800
is that what you are looking for, what the difference between 1760 and 1800 would be ?
I thought you had it already shot it and wanted to know why you are seeing variations from day to day ?
If you know your 1 Mile dope, go to a place like JBM put in your data and match it to 21.1 at 1760 then do it with 1800 it should be super close within the plate size.
I would at least use .3 more potentially .5 as your load does not appear very fast, that is more elevation than my 6.5CM at 1780 here in CO
We use around 19.8 mils at 1760 and that translate to roughly 20.5 at 1800
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Deleted member 113831
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Over 1800 yards there is just so much room for terrain features to affect light and wind, it is really impossible for anyone to tell you without being there to look at it. Even then, it can be so complex as to be just a SWAG anyway.
In ELR, the game is adjusting the second shot quickly and accurately. Getting the first one on target is of course desirable, but not always doable.
In ELR, the game is adjusting the second shot quickly and accurately. Getting the first one on target is of course desirable, but not always doable.
Well, not exactly. I wouldn't adjust any inputs yet, just observer the occurrence and note the conditions. The issue is you need some time to isolate factors, and frankly there is potentially a lot of different effects at play. What you want to do is start building up a mental data base of different effect and the conditions as they manifest them selves, your notes can help with this. Ultimately as Frank pointed out there is no good formulas for correcting some of these variables in the amount of time given, ELR is one of these tricky areas where the analytical approach will only get you so far. Sometimes there are simply to many variables at distance to arrive at an exact solution, this is where developing an intuitive understanding of the effects allows you to get pretty close drawing of the collective of your experience.
kinda cool to see those numbers.
my 260 is 22.6 on most summer days here at a mile.
2230 elevation and 3400 DA.
That spot varies from 21..30 to 23.8 throughout the year.
Yea I finally got serious and started taking notes and kick myself for not starting earlier.
My 7 saum was 19.1 at 1810 a few days ago.
2400 with a chilly 1311 DA.
Sir, that was an excellent synopsis. Varying terrain is best dealt with when one has the time to gain some familiarity. However, given a situation when that's not possible, one must be able to extrapolate previous experience in similar terrain. This is the basis for collecting dope data.
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