Range Report JBM Ballistics & Wind

[One_Man]

I am trying to learn how to shoot F-Class on my own. I want to know how much of a hold off is needed for a 10 mph 90 degree crosswind at 550 yards with a .308 Berger 175gr Match Target BT Long Range bullet at 2600 fps assuming a 100 yard zero. According to JBM Ballistics its 20" of wind drift. Does that mean its a 20" hold off of the bullseye? Just seems like a lot to me.

 

[Jumper]

Re: JBM Ballistics & Wind

JBM is calculating your solution for a target that is moving 10mph. If this is not correct then it will give you incorrect results.

 

[vinconco]

Re: JBM Ballistics & Wind

your data is correct as entered. By comparison my 308 175smk's @ 2650 using the G1 drag function drift 23" @ 550 yards or 4.18 moa

 

[ARP]

Re: JBM Ballistics & Wind

You may find a better option is to get your wind values for a 1 mph wind and then multiply that by the various wind speeds you encounter later.

 

[Lindy]

Re: JBM Ballistics & Wind

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">JBM is calculating your solution for a target that is moving 10mph.</div></div>

Umm, nope. The lead it calculates for a moving target is reported separately in the "lead" column. The wind column is not affected by that value.

 

[wadcutter]

Re: JBM Ballistics & Wind

The JBM wind calculation is very accurate.

I shot one target at right angles to the wind and measured bullet drift hold off to a target at 1000 yards. I then used this wind value for another target that was at an angle to the wind with the wind comming in at 1 O'clock. I shot with this correction out to 1543 yards and was spot on for windage correction on the target. Very impressed.

I use a standard 1 mph wind value and calculate a drop chart for that. I then just multiply the actual wind value by the result.

Actually shooting at 90 degrees to the wind is the best way to measure the wind. A wind meter only measures the wind at the station point, not over the long distance where it can change.
If your actual wind correction doesn't line up with JBM then it is because your inputs are not right.

 

[jbmillard]

Re: JBM Ballistics & Wind

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Parkincense</div><div class="ubbcode-body">I am trying to learn how to shoot F-Class on my own. I want to know how much of a hold off is needed for a 10 mph 90 degree crosswind at 550 yards with a .308 Berger 175gr Match Target BT Long Range bullet at 2600 fps assuming a 100 yard zero. According to JBM Ballistics its 20" of wind drift. Does that mean its a 20" hold off of the bullseye? Just seems like a lot to me.
</div></div>

I suspect the windage is slightly more than that. Note that the windage at 100 yards is zero -- less than that it is negative -- you have "windage correction for zero range" on. This is fine if you zeroed with that wind, if you zeroed with no wind, then it will be slightly more.

Brad