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Old May 28, 2019, 04:14 PM   #1
robrob
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Moving Target Question

I'm using Applied Ballistics Mobile App for ballistic solutions. When I put in a wind from 3 o'clock it gives a right correction which makes sense. We have to adjust the turrets to point the barrel to the right, into the wind, to hit the target.

Here's the confusing part. When I put in a target moving from 3 o'clock (right to left) I also get a right turret correction. Shouldn't I need a left correction to lead the target moving to the left?

In other words, with a wind coming from the right we point the barrel to the right, into the wind, to hit the target but with a target moving to the left we need to point the barrel to the left to lead the target, right?

I asked Applied Ballistics about this and they replied that wind and target from 3 o'clock work the same way--they both get a right correction. That doesn't seem right to me. What am I doing wrong here?

Thanks in advance for the help,

Rob
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Old May 28, 2019, 04:38 PM   #2
Rangerrich99
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Never used AB, so this is a guess.

I think what they're saying is to eliminate the wind variable, so add in the right correction. Now all that's left is the moving target correction, so you should be able to lead as if there's no wind?
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Old May 28, 2019, 06:00 PM   #3
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Wind generally should be added if the target is moving in the same direction and deducted if moving in the opposite direction. If the target is moving slower than the wind component there may be a reduction lead, but not a complete direction change.
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Old May 28, 2019, 06:28 PM   #4
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Depends on strength of wind and speed of target. What was the wind speed and target speed?

Depending on distance and the chosen caliber, a stout 12-15 mph wind could be enough to cause just this situation if the target is only walking 3 mph or so.

If wind alone requires a 1.5 mil hold (over 5 MOA) into the wind, but the mover requires only a .5 mil hold (almost 2 MOA) ahead of it , you would still have to hold into the wind. (This is just a gross generalization)

Also, I wouldn't recommend dialing for windage compensation. (Just my opinion.)
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Old May 28, 2019, 06:49 PM   #5
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Quote:
Originally Posted by Picher View Post
Wind generally should be added if the target is moving in the same direction and deducted if moving in the opposite direction.
I think you meant the opposite? Both wind and mover going from right to left means one must hold into the wind (right), which is opposite from the direction ahead of the mover (left). Hence, there will be a reduction in total hold when they are in the same direction.

However, not to insult anyone's intelligence, a 5 mph wind in the same direction as a 5 mph mover DO NOT necessarily cancel each other out.
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Old May 28, 2019, 09:06 PM   #6
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I've never heard of using turret adjustment to "lead" a moving target (on a man portable gun anyway).
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Old May 28, 2019, 09:49 PM   #7
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I used a 10mph wind from 3 o'clock and a 3mph moving target from 3 o'clock. Range is 1000 yards.



Wind is 10mph from 3 o'clock
Target is moving to the left, from 3 o'clock at 3mph.

AB Mobile gives a wind correction of 1.3 mils right and a lead of 2 mils to the right. The numbers are independant. If you set wind to 0 the lead stays the same. If you set the target speed to 0 the wind correction stays the same.

Since the lead is independent, shouldn't it be a left 2 mils for a moving target moving to your left?

Said another way, with the wind from 3 o'clock we offset to the right, into the wind. If a target is moving from 3 o'clock it's moving to our left so we would offset left to lead the target, correct?
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Old May 28, 2019, 11:02 PM   #8
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What is the time of flight of the bullet?

With the target moving to the left with the wind, the rifle's windage correction to the right must be reduced. If the target is moving to the left fast enough, the windage correction could become zero and negative (to the left). The time of flight is the determining factor.

We need to know the muzzle velocity too.

-TL

Sent from my SM-G930T using Tapatalk
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Old May 28, 2019, 11:03 PM   #9
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That is rather peculiar.

Are you certain you were able to put a mover direction? Again, not trying to insult your intelligence.

I have seen software that doesn't do very well with movers.
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Old May 29, 2019, 04:14 AM   #10
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Are you certain you were able to put a mover direction? Again, not trying to insult your intelligence.

Yes, I confirmed in the PDF instructions, target movement is "From" the clock position, just like the wind.

Let's disregard the wind, with wind set to 0, target moving from 3 o'clock at 3mph Applied Ballistics Mobile shows a correction of R2.0 mils. Since the target is moving to the shooter's left shouldn't the lead be L2.0 mils?
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Old May 29, 2019, 06:37 AM   #11
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Compensation for wind deflection of the bullet would very seldom equal lead required to match the movement of a physical target.
Using some rough calculations and quite possibly making an error, I figured that a wind deflection of 3" in 100 yards with a flight time of 0.1 second would equal a travel speed of 1.7 MPH.
To compensate for a target moving left, you would have to adjust the crosshairs to the RIGHT.That pushes the POI LEFT on the target. Pay attention as I said "move the crosshairs right--not POI as most adjustments are labelled.
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Old May 29, 2019, 06:40 AM   #12
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Quote:
Originally Posted by robrob View Post
[I]Let's disregard the wind, with wind set to 0, target moving from 3 o'clock at 3mph Applied Ballistics Mobile shows a correction of R2.0 mils. Since the target is moving to the shooter's left shouldn't the lead be L2.0 mils?
Yes.
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Old May 29, 2019, 09:24 AM   #13
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Quote:
Said another way, with the wind from 3 o'clock we offset to the right, into the wind. If a target is moving from 3 o'clock it's moving to our left so we would offset left to lead the target, correct?
Said that way, it is correct.

And I'm fairly confident the math part of your program is giving you correct number amounts.

Now, here's what I'm wondering, the program clearly "knows" that wind from 3 O'clock is blowing right to left. It tells you to correct to the right. But does it "know" that the target "moving from 3 O'clock is moving to the left? And that it is different than the wind? OR, perhaps it just "sees" an input variable "moving to the left", so it tells you to aim right"

If the target is moving, aim in the "downwind" direction (the direction the target is moving) For wind, aim OPPOSITE the direction the wind is moving (upwind). It doesn't seem your program is taking that into account.
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Old May 29, 2019, 10:18 AM   #14
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The directions for AB Mobile clearly state that a moving target moves FROM the clock direction, so from 3 o'clock the target is moving to the left and the lead must also be to the left.

I have sent Applied Ballistics another email about this. This time I left out the wind to lower the complexity of the issue.
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Old May 29, 2019, 11:47 AM   #15
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robrob,

*With no input for wind* If you put the mover as going from LEFT to RIGHT, does it still give you the right hold?
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Old May 29, 2019, 01:10 PM   #16
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With no input for wind* If you put the mover as going from LEFT to RIGHT, does it still give you the right hold?

No, I get L2.0 mils when target direction is from 9 o'clock at 3mph at 1000 yards.
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Old May 29, 2019, 01:49 PM   #17
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Then it would appear that whatever the .pdf says, the clock direction in regards to the mover is the direction of travel, not the direction of origin.
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Old May 29, 2019, 02:00 PM   #18
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From the AP instructions:

"Move Angle –  [Degrees or Clock direction] The direction of travel for a moving target either degrees or clock direction.  A direction is named from where the target is coming from."

It looks like the software is behaving exactly the opposite.
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Old May 29, 2019, 02:26 PM   #19
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Yes, they need to correct either the instructions or the program. Changing the code would make more sense so both wind and the target direction would be "from".
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