Balistic calculator surprise

rclouse79

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I was playing around with the Hornady ballistic calculator on my phone. It shows 0.4 mrad adjustment at 200 yards with no wind. A 12 mph cross wind blowing left to right it shows 0.59 mrad. A 12 mph crosswind blowing right to left shows 0.20 mrad adjustment. I would have guessed a cross wind would not have changed the drop at a given distance, and was even more surprised the direction of the cross wind had an opposite effect on drop. I am ready to be educated. I am guessing it has something to do with the spin of the bullet.
 

Wrench

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With that much difference you must have the twist wrong and/or an incredibly low bc.

The bullet will yaw with the wind and try to climb the breeze to some extent....but it should be closer a tenth or two of a mil.
 
OP
rclouse79

rclouse79

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With that much difference you must have the twist wrong and/or an incredibly low bc.

The bullet will yaw with the wind and try to climb the breeze to some extent....but it should be closer a tenth or two of a
The percent difference between the values decreases at longer range. At 500 yards with a 10 mph crosswind left to right was 2.78 mil and right to left was 2.46 mil. I double checked my inputs last year and got everything to check out at the range. I will stick to chip shots in the wind until I have a chance to verify in windy conditions.
 

hereinaz

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Its what they call aerodynamic jump.

A left to right wind deflects a bullet down. A right to left deflects it up.

Technically it is the precession of the bullet, and the wind destabilizing the bullet.
 
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Its what they call aerodynamic jump.

A left to right wind deflects a bullet down. A right to left deflects it up.

Technically it is the precession of the bullet, and the wind destabilizing the bullet.

My understanding is that aerodynamic jump is frequently over stated by Applied Ballistics software. I’m not sure what system the OP is using but that seems to be the case here doesn’t it? 4 tenths at 200 yds with only a 12 mph cross wind seems crazy.
 

Wrench

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My understanding is that aerodynamic jump is frequently over stated by Applied Ballistics software. I’m not sure what system the OP is using but that seems to be the case here doesn’t it? 4 tenths at 200 yds with only a 12 mph cross wind seems crazy.

Agreed. I thought perhaps he has a 8 twist 45-70 or something far enough from what I've experienced to learn a headache.
 
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rclouse79

rclouse79

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If anyone is bored, I would be interested what your calculator gives for drop at 200 yards with no wind and a 12 mph crosswind each way. I am shooting a .270 tikka with a 130 grain barnes ttsx bullet. If I entered something incorrectly I would like to remedy it.
 

Wrench

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My 270 10 twist shows .2/.4MILS at 200 with a 150lrab. I don't have any other data loaded.

My 243 105amax is. 4/.4 also 10 twist.

308....is .5/.5...
 

Smokeslider

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@rclouse79

I ran it in Shooter, with factory spec of 3060 ft/sec. Not sure your twist but appears the new T3X superlite in .270 is 1:10.

200 yd drop when zeroed at 100= 0.5 Mils (1.7moa)


Wind 12mph=R .5mils when wind is 90 degrees
Wind 12mph=L .5mils when wind is 270 degrees.

Appears the shooter app thinks the effects should be very similar as far as bullet drift.
 
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rclouse79

rclouse79

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@rclouse79

I ran it in Shooter, with factory spec of 3060 ft/sec. Not sure your twist but appears the new T3X superlite in .270 is 1:10.

200 yd drop when zeroed at 100= 0.5 Mils (1.7moa)


Wind 12mph=R .5mils when wind is 90 degrees
Wind 12mph=L .5mils when wind is 270 degrees.

Appears the shooter app thinks the effects should be very similar as far as bullet drift.
Just to double check, the vertical adjustment was the same regardless of the wind, or were the last two .5 mils the windage?
 

Smokeslider

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Just to double check, the vertical adjustment was the same regardless of the wind, or were the last two .5 mils the windage?
Elevation was always the same (.05 mils) regardless of the wind applied. Coincidental enough, your original scenario had all outputs of 0.05 mils.
 

Smokeslider

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Firearm: 270 Test
Barrel Twist
1 in 10.000 in
Twist Dir.
Right
Sight Height
0.750 in
Sight Offset
0.000 in
Elev. CF
1.00000
Wind CF
1.00000
Ammo: Barnes 130gr TTSX BT
Bullet Diameter
0.277
Bullet Weight
130.00 gr
Bullet Length
1.3220 in
Atmos. Std.
ICAO
Muzzle Vel.
3060.00 fps
Vel. Varation
0.00 fps
Drag Model
G1
Powder Temp
55 °F
BC(s)
[email protected]
Zero Range
100 yd
Zero Height
0.000 in
Zero Offset
0.000 in
Atmosphere
Altitude
0.00 ft
Baro. Press
29.92 inHg
Temp
59.00 °F
Humidity
0.000 %
Shot Data
Move Speed
10.00 mph
Move Angle
90.00 °
Look Angle
0.00 °
Spin Drift
Off
Wind Speed
12.00 mph
Wind Angle
90.00 °
Coriolis Effect
Off
Latitude
0.000 °
Azimuth
0 °


Range
(yd)
Path
(in)
Path
(mils)
Drift
(in)
Drift
(mils)
Velocity
(fps)
Energy
(ft-lbs)
TOF
(s)
500
-50.7
U2.8
-26.8
R1.5
1938.4
1084.6
0.617
450
-38.2
U2.4
-21.2
R1.3
2037.3
1198.1
0.541
400
-27.8
U1.9
-16.4
R1.1
2138.6
1320.1
0.470
350
-19.4
U1.5
-12.3
R1.0
2243.2
1452.4
0.401
300
-12.6
U1.2
-8.8
R0.8
2350.9
1595.3
0.336
250
-7.4
U0.8
-6.0
R0.7
2461.4
1748.8
0.273
200
-3.7
U0.5
-3.8
R0.5
2574.5
1913.1
0.214
150
-1.2
U0.2
-2.1
R0.4
2690.8
2089.9
0.157
100
0.0
0.0
-0.9
R0.3
2810.0
2279.1
0.102
50
0.1
D0.1
-0.2
R0.1
2932.2
2481.7
0.050
0
-0.8
0.0
-0.0
0.0
3060.0
2702.8
0.000
 
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Dec 29, 2016
Messages
690
Location
Reno, NV
My understanding is that aerodynamic jump is frequently over stated by Applied Ballistics software. I’m not sure what system the OP is using but that seems to be the case here doesn’t it? 4 tenths at 200 yds with only a 12 mph cross wind seems crazy.

EXACTLY. I tested the Applied Ballistics many times and found that indeed, aerodynamic jump is way way over stated.
 
OP
rclouse79

rclouse79

WKR
Joined
Dec 10, 2019
Messages
1,727
EXACTLY. I tested the Applied Ballistics many times and found that indeed, aerodynamic jump is way way over stated
I am wondering if it would be best to plug in the distance to the target and dial your vertical adjustment, then put the wind in and adjust for windage ignoring any change to the vertical adjustment. I will be keeping my shots on game to reasonable distances so I think I am most likely worrying about something that won't be much of a factor.
 
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