Balistic calculator surprise

[rclouse79]

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]

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.

 

[rclouse79]

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]

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.

 

[wind gypsy]

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.

 

[rayporter]

 

[BigskyRF]

View attachment 284064

Is this for a set MPH of wind or is this just in general winds effect on flight path?

 

[Wrench]

Is this for a set MPH of wind or is this just in general winds effect on flight path?

General effects....and lots of variables.

 

[Wrench]

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.

 

[BigskyRF]

General effects....and lots of variables.

Gottcha. Interesting visual for sure.

 

[rclouse79]

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]

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]

@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.

 

[rclouse79]

@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?

 

[rayporter]

the pic applies to rimfire also-but you have to have a benchrest rifle to see it at 50 yd.

 

[Smokeslider]

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]

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​

 

[NevadaZielmeister]

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.

 

[rclouse79]

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.

 

[wind gypsy]

You should be able to disable aerodynamic jump in your solver.