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Posted: 5/9/2022 9:53:47 AM EDT
Asking the more experienced medium distance shooters here......

Yesterday was windy, so I headed out to the range to work on wind calls at medium distances of 300 to 500 yards.  

Equipment: Savage 12BVSS in .223 with a Swarovski Z5 3.5x18 (BRH reticle).  

Ammo: reloads verified to match the ballistics of Federal Gold Medal Match with a 69 grain SMK.  

Conditions:  6% humidity, temperature 93 degrees, wind varying from 7 to 18 mph coming from behind the shooting position, varying slightly from 7 to 8 o'clock (quartering, not full value).  

Range setup:  shooting position top of a ridge, target was a 10" square plate on another ridge 492 yards away.  There is a small canyon or wash in between the ridges.  If you're familiar with the Cowtown range outside of Phoenix, I was on west platform 2.  

The wash in between the ridges is roughly 30-40 yards deep, and the target was approximately 50 yards higher than the shooting position.  

Incredibly accurate MS Paint side view:



The lateral hold off for the maximum wind gusts was about 2 mils.  What confused me at the time was that I also had to change my vertical hold off to what would normally be my 450 yard hold.  At the time I just dealt with it, but it's been bugging me ever since.  

My theory is that the wind was flowing through the canyon/wash, striking the face of the mountain, and creating an upward current as it flowed over the ridge that lifted the bullet as well as moving it sideways.  

Am I completely off base here?  This was not the first time I've experienced this effect, but it's the first time I really thought about what was happening.  

Feedback from the hive would be appreciated just so I can sleep tonight.  

Link Posted: 5/9/2022 10:00:38 AM EDT
[#1]
Link Posted: 5/9/2022 10:03:44 AM EDT
[Last Edit: Millennial] [#2]
Does aero jump (at the muzzle) account for your problem? It’s usually pretty small though (<0.5moa up or down)
Link Posted: 5/9/2022 12:41:38 PM EDT
[Last Edit: MSC182] [#3]
More than likely it was the inclination of the shot, not the wind, which had you hitting high.

Link
Link Posted: 5/9/2022 2:28:50 PM EDT
[#4]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By MSC182:
More than likely it was the inclination of the shot, not the wind, which had you hitting high.

Link
View Quote



Good point. The rangefinder is supposed to account for that, but it may have changed modes to direct reading instead of angle compensated.  I’ll check that when I get home.
Link Posted: 5/9/2022 3:55:02 PM EDT
[#5]
Link Posted: 5/10/2022 2:27:22 AM EDT
[#6]
Sounds more like angle than wind..line of sight length 492yards versus horizontal length 450 yards..gravity is only pulling down on the bullet for 450 yards of the 492 yards the bullet traveled...
Link Posted: 5/10/2022 6:30:45 AM EDT
[#7]
Curious to what time of day?

As the earth warms up, the warmed air tends to move “up” the sides of mountains.
Link Posted: 5/10/2022 9:23:25 AM EDT
[#8]
Confirmed that both range finders (Sig Kilo 1000 and Meopta Meopro binoculars) are still set to angle compensation.  Both of them gave the same reading.  

Time of day was 13:00 to 15:00.  


Link Posted: 5/10/2022 8:07:37 PM EDT
[Last Edit: Henny] [#9]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By kermit:
Confirmed that both range finders (Sig Kilo 1000 and Meopta Meopro binoculars) are still set to angle compensation.  Both of them gave the same reading.  

Time of day was 13:00 to 15:00.  


View Quote


I see you’re in Arizona, from 1300-1500, is that when things go from, “damn it’s hot!”, to “Jeeeeezus….it’s hot!”?

Thermal air movement up the hillside could be a cause.
Link Posted: 5/13/2022 11:35:55 PM EDT
[#10]
Link Posted: 5/15/2022 9:09:22 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Skg_Mre_Lght:
Yes, I've had midday up drafts add a mil and a half or better shooting in the hills.
View Quote

My experience as well.  Makes you look at your data and go huh?
Link Posted: 5/15/2022 11:17:50 PM EDT
[#12]
Hunters know thermals very well to keep our scent from reaching whatever prey we are after.
Cool mornings breeze down hill.
Slowly warming breeze can change to follow sidehill contours.
As it warms more thermals change to breeze uphill.
Weather can change all these variables.

Degree of angle and elevation also plays a roll in trajectory to the target.
Short to moderate range depending on target size usually you do not need to worry as much about it.
Long range is entirely different obviously as the amount of variables increase including your bullets trajectory is compounded by loss of velocity as well, and wind drift adjustments need to be accurately compensated for.

The more you shoot in various conditions the more you learn.
Getting a good wind reading at your postion doesn't mean the thermals at your target at long range havent changed multiple times due to land features.
It's challenging and can at times be frustating to even the best shooters.

The good thing is you noticed what was going on so your well on your way to figuring out the variables than most ever will.
Link Posted: 6/4/2022 8:47:08 PM EDT
[#13]
Yeah wind hitting a face rides up. Watch para sailers, they ride those ridges all day
Link Posted: 7/11/2022 7:52:44 PM EDT
[Last Edit: Blowout] [#14]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By AKSnowRider:
Sounds more like angle than wind..line of sight length 492yards versus horizontal length 450 yards..gravity is only pulling down on the bullet for 450 yards of the 492 yards the bullet traveled...
View Quote

I believe he's using a 450yd hold.
Attachment Attached File


ETA: Let me know if I'm missing something... in learning mode here. :)
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