First off, Hello. 1st post here but I have been reading/learning from this site for around a year. My question is, when using ballistic calculators(I use JBM) has any one ever used the data you recieve and have it match perfectly to the "real world" data you get from shooting down range.I have always plugged in all the data points but always seems to be off some +/- a couple of MOA.So when I use the calculators I mainly just use them to get me on paper/steel then adjust from there, is this the norm?
Range Report Ballistic calculators vs real range data?
- Thread starter jac74
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Re: Ballistic calculators vs real range data?
No to your first question and yes to the second!!!
There are just to many variables both mechanical and in the atmosphere.
I have made first round hits out to 700 yds. using "conjured-up" data, but there is no substitute for actual field data and firing solutions...IMHO
No to your first question and yes to the second!!!
There are just to many variables both mechanical and in the atmosphere.
I have made first round hits out to 700 yds. using "conjured-up" data, but there is no substitute for actual field data and firing solutions...IMHO
Re: Ballistic calculators vs real range data?
Field data rules, but just take into account that not all field data is completely trustworthy...
There are many environmental factors (wind up/dow drafts, temperature and pressure variations, etc.) that can make your POI different a some ranges compared to the projected trajectory. If you take your computer data and it matches at all ranges 100-1000 m but is off 1.5 MOA at 600 (specially if you only check this once, not repeatedly), there is likely something wrong with the conditions or the shooter.
Field data rules, but just take into account that not all field data is completely trustworthy...
There are many environmental factors (wind up/dow drafts, temperature and pressure variations, etc.) that can make your POI different a some ranges compared to the projected trajectory. If you take your computer data and it matches at all ranges 100-1000 m but is off 1.5 MOA at 600 (specially if you only check this once, not repeatedly), there is likely something wrong with the conditions or the shooter.
Re: Ballistic calculators vs real range data?
Ballistics is a mature science, and solvers like JBM are implementing the science correctly. So if you fully understand how to use the program, and all your instruments are calibrated (chronograph, kestrel, etc) and you give the program accurate inputs, the output WILL be accurate.
There's another 'gotcha'...
Will you use the data properly? Meaning, do you understand how much your scope reticle <span style="font-style: italic">actually</span> moves each click? If you're assuming it moves 1/4 MOA per click and you haven't ever checked it, it's not fair to conclude that the program is giving you bad dope. It might be the scope that's not <span style="font-style: italic">applying</span> the right dope.
So to answer your question and to echo the answers above:
Yes the program is accurate, and
Yes it's common for shooters to 'observe' different trajectories than predicted because of imperfect application.
The more careful you are about your application and the more you know about ballistics, the closer your predicted and actual trajectory will be.
-Bryan
ETA:
Here's a great write up on: sources of ballistic program inaccuracies.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Programs/
It's required reading for anyone who wants to understand the use and limitations of ballistic programs.
Ballistics is a mature science, and solvers like JBM are implementing the science correctly. So if you fully understand how to use the program, and all your instruments are calibrated (chronograph, kestrel, etc) and you give the program accurate inputs, the output WILL be accurate.
There's another 'gotcha'...
Will you use the data properly? Meaning, do you understand how much your scope reticle <span style="font-style: italic">actually</span> moves each click? If you're assuming it moves 1/4 MOA per click and you haven't ever checked it, it's not fair to conclude that the program is giving you bad dope. It might be the scope that's not <span style="font-style: italic">applying</span> the right dope.
So to answer your question and to echo the answers above:
Yes the program is accurate, and
Yes it's common for shooters to 'observe' different trajectories than predicted because of imperfect application.
The more careful you are about your application and the more you know about ballistics, the closer your predicted and actual trajectory will be.
-Bryan
ETA:
Here's a great write up on: sources of ballistic program inaccuracies.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Programs/
It's required reading for anyone who wants to understand the use and limitations of ballistic programs.
Re: Ballistic calculators vs real range data?
I use both my real world data and what i get from my ballistic programs!!
Thats why having, using, and tracking your shooting in a data book will allow you to sit back look at the shots and compare the data. It will help point out things after your shooting session when you take a step back and scratch your head trying to figure it all out!!
Happy Shooting
I use both my real world data and what i get from my ballistic programs!!
Thats why having, using, and tracking your shooting in a data book will allow you to sit back look at the shots and compare the data. It will help point out things after your shooting session when you take a step back and scratch your head trying to figure it all out!!
Happy Shooting
Re: Ballistic calculators vs real range data?
I use JBM to go to matches and it's never been off more than .2 mils at 1000. Inside that it's pretty close to right on. Close enough for me to win matches. I only have a 400 yard range at home so I can't get real world data.
Something to think about though is that your data you get out of a ballistics program is only as good as the data you put in. Garbage in, garbage out is the old saying.
I use JBM to go to matches and it's never been off more than .2 mils at 1000. Inside that it's pretty close to right on. Close enough for me to win matches. I only have a 400 yard range at home so I can't get real world data.
Something to think about though is that your data you get out of a ballistics program is only as good as the data you put in. Garbage in, garbage out is the old saying.
Re: Ballistic calculators vs real range data?
Thanks for all the info, I read the write up and, it makes perfect sence. I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. As far as all of the other possibilites/variables it could be any or a little of them all working together to make this happed. But more than likely its the dope behind the scopes fault, I still have problems with him at times.
Thanks for all the info, I read the write up and, it makes perfect sence. I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. As far as all of the other possibilites/variables it could be any or a little of them all working together to make this happed. But more than likely its the dope behind the scopes fault, I still have problems with him at times.
Re: Ballistic calculators vs real range data?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO
Re: Ballistic calculators vs real range data?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AQC440</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO </div></div>
AQC raises a good point. I have a Vortex Razor also. The turrets are off just far enough that the 7.2 mil predicted by JBM is actually 7.0 on the scope for 1000 yds.
I knew this ahead of time because I validated the scope at 100 yds. on my shop door using dots at +-10 mil elevation and +-5 mil wind.
Once you begin to collect field data, it's not a big deal. But it helps to know ahead of time if the scope is going to be optimistic or pessimistic.
John
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AQC440</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO </div></div>
AQC raises a good point. I have a Vortex Razor also. The turrets are off just far enough that the 7.2 mil predicted by JBM is actually 7.0 on the scope for 1000 yds.
I knew this ahead of time because I validated the scope at 100 yds. on my shop door using dots at +-10 mil elevation and +-5 mil wind.
Once you begin to collect field data, it's not a big deal. But it helps to know ahead of time if the scope is going to be optimistic or pessimistic.
John
Re: Ballistic calculators vs real range data?
There certainly are plenty of outside variables. However, like Bryan said, the science is there. I found I got closer results when I figured out the inputs and paid closer attention to getting them right. Using Litz' G7 BCs, up-to-date station pressure from my GPS, consistently measured velocity readings, and temperatures has helped.
One thing that is a little bit of a trade off is that I zero @ 100 yards. I noticed once that when I later changed pressure, temperature and humidity considerably, my drops didn't vary enough to matter until I got past 400 yards. I contacted the author of Ballistic about this and he suggested trying a 300-600 yard zero to see a difference at the zero when current conditions vary from those at the time the rifle was zeroed.
Sure enough, that does make a difference. At a 600 yard zero, the difference would be 2.7" for this particular load. Well, the difference in drop @ 100 yards was still 4.0 mils so it had no net effect. And there are some significant negatives to having a zero out past 100 when you have a zero-stop scope and are trying to eliminate as many variable as possible (wind, mostly) when zeroing.
So get the basic data right and your ballistics calculations will be pretty close...better than a guess by far. But don't sweat it too much and verify with as much shooting as you can.
There certainly are plenty of outside variables. However, like Bryan said, the science is there. I found I got closer results when I figured out the inputs and paid closer attention to getting them right. Using Litz' G7 BCs, up-to-date station pressure from my GPS, consistently measured velocity readings, and temperatures has helped.
One thing that is a little bit of a trade off is that I zero @ 100 yards. I noticed once that when I later changed pressure, temperature and humidity considerably, my drops didn't vary enough to matter until I got past 400 yards. I contacted the author of Ballistic about this and he suggested trying a 300-600 yard zero to see a difference at the zero when current conditions vary from those at the time the rifle was zeroed.
Sure enough, that does make a difference. At a 600 yard zero, the difference would be 2.7" for this particular load. Well, the difference in drop @ 100 yards was still 4.0 mils so it had no net effect. And there are some significant negatives to having a zero out past 100 when you have a zero-stop scope and are trying to eliminate as many variable as possible (wind, mostly) when zeroing.
So get the basic data right and your ballistics calculations will be pretty close...better than a guess by far. But don't sweat it too much and verify with as much shooting as you can.
Re: Ballistic calculators vs real range data?
Think of it like this:
Given that you KNOW the MV of your load, you can INITIALIZE the table entries with respect to distance, conditions, ...
However, as you acquire field data on that load in your rifle under the same or different field conditions, that real data overrides the ballistics caluclator outputs. That is: Real >= Calculated; but Calulated >= Guess.
Think of it like this:
Given that you KNOW the MV of your load, you can INITIALIZE the table entries with respect to distance, conditions, ...
However, as you acquire field data on that load in your rifle under the same or different field conditions, that real data overrides the ballistics caluclator outputs. That is: Real >= Calculated; but Calulated >= Guess.
Re: Ballistic calculators vs real range data?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AQC440</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO </div></div>
AQC440,
Thanks, that is a real handy site in your post. It takes the BS out of some of the things that I have been doing.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AQC440</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jac74</div><div class="ubbcode-body"> I trust my scope adjustments, I have box tested it several times, its a Vortex Razor HD. </div></div>
With human error and other variables involved, a simple box test isn't going to tell you if your scope is dialing .350 instead of .250! If you want to do this correctly then take the time to do "Optically Checking Rifle Scopes"
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
Scopes costing thousands of dollars more then I could ever afford have this issue as well as lesser scopes.
Doing the above will take one more variable out of the equation...Again IMHO </div></div>
AQC440,
Thanks, that is a real handy site in your post. It takes the BS out of some of the things that I have been doing.
Re: Ballistic calculators vs real range data?
If you use QL and it´s Quick Target Unlimited (QTU) software with Radar Data for Lapua bullets or some selected military bullets (example: 175 Mk for 308) and put in all environmental data corrctly and have an accurate muzzle velocity of your load at the shooting temprature it will track the bullet path really well.
If you do not have radar data for your bullet then use G7 function and Litz G7 bullet data.
QTU is included in the QL package so you money is well spent with QL.
If you use QL and it´s Quick Target Unlimited (QTU) software with Radar Data for Lapua bullets or some selected military bullets (example: 175 Mk for 308) and put in all environmental data corrctly and have an accurate muzzle velocity of your load at the shooting temprature it will track the bullet path really well.
If you do not have radar data for your bullet then use G7 function and Litz G7 bullet data.
QTU is included in the QL package so you money is well spent with QL.
Re: Ballistic calculators vs real range data?
I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.
I also came to the realization that I need a good optic. My clarity sucked.
I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.
I also came to the realization that I need a good optic. My clarity sucked.
Re: Ballistic calculators vs real range data?
...ShooterBallistics + DroidX + GPS = real world.
..once I save up enough $$ for a Kestrel
ShooterBallistics + DroidX + Kestrel = really real world!
...ShooterBallistics + DroidX + GPS = real world.
..once I save up enough $$ for a Kestrel
ShooterBallistics + DroidX + Kestrel = really real world!
Re: Ballistic calculators vs real range data?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EricF517</div><div class="ubbcode-body">I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.
I also came to the realization that I need a good optic. My clarity sucked.</div></div>
What caliber? You might want to check to see how your scope tracks if that's a .308.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EricF517</div><div class="ubbcode-body">I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.
I also came to the realization that I need a good optic. My clarity sucked.</div></div>
What caliber? You might want to check to see how your scope tracks if that's a .308.
Re: Ballistic calculators vs real range data?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EricF517</div><div class="ubbcode-body">I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.</div></div>No offense ('cause I know I've certainly been there) but are you sure you are getting the inputs entered correctly? Both those apps are very good. But back when I didn't know the difference between station and corrected pressure and how the latter requires knowing exact altitude, I didn't get correct output. If you can get an accurate BC, using the proper drag model for the bullet (typically G1 or G7), muzzle velocity, temperature and either station pressure or corrected pressure + altitude, you should get real close to real-world results.
One thing I couldn't overcome until I got Litz' book was that the advertised BC for one of my bullets was way off. When I switched to his BC it brought drops into line.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EricF517</div><div class="ubbcode-body">I had the same issue with JBM the other day. It told me 8moa, ShooterBallistics on my Android told me 8.25moa, and my actual was 5.75moa at 400yds.</div></div>No offense ('cause I know I've certainly been there) but are you sure you are getting the inputs entered correctly? Both those apps are very good. But back when I didn't know the difference between station and corrected pressure and how the latter requires knowing exact altitude, I didn't get correct output. If you can get an accurate BC, using the proper drag model for the bullet (typically G1 or G7), muzzle velocity, temperature and either station pressure or corrected pressure + altitude, you should get real close to real-world results.
One thing I couldn't overcome until I got Litz' book was that the advertised BC for one of my bullets was way off. When I switched to his BC it brought drops into line.
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