Range Report Which Ballistic Calculator Is Correct ??

[Muttt]

I was at the range getting velocities and working up some data to make range cards. My buddy had EXBAL on his palm pilot and ran the numbers. His data had me about an inch or two low at 545 yards. But, since I don't have Exbal and we didn't have a printer at the range, I couldn't reproduce the data when I got home. So, I ran the numbers again on JBM (online) and also ran the numbers on Vortex Optics online ballistic calculator. But, not only did the numbers not match what Exbal gave me, but they didn't match each other. So, I have no idea which calculator to use. Any idea why I am getting so many different number since I am pumping the same data into each program?????

Here are the numbers I am using ............

Bullet 168gr AMAX
BC .4758
Velocity 2558 fps
Site Height 1.875
Altitude 500
Pressure 30
Humidity 49
Temp 45

When putting it into JBM I get .........

yad inch MOA velocity
100 -0.0 -0.0 0.0 0.0 2373.0 2.155 2100.2 0.122 0.0 0.0
200 -4.3 -2.1 0.0 0.0 2195.6 1.994 1798.0 0.253 0.0 0.0
300 -15.8 -5.0 0.0 0.0 2025.8 1.840 1530.7 0.395 0.0 0.0
400 -35.9 -8.6 0.0 0.0 1864.0 1.693 1295.9 0.550 0.0 0.0
500 -65.9 -12.6 0.0 0.0 1710.9 1.554 1091.8 0.718 0.0 0.0
550 -85.3 -14.8 0.0 0.0 1637.9 1.487 1000.6 0.807 0.0 0.0

When I put it into the Vortex Ballistic Calculator I get ..........

Yrd Inch MOA
100 0.0" -0.0
200 -3.8" -1.8
300 -13.9" -4.4
400 -30.6" -7.3
500 -54.6" -10.4
550 -69.6" -12.1

I can't remember all the info from Exbal but it was different, it worked out to be 57 (1/4 MOA) clicks at 545 yards or 14.25 MOA.

 

[azimutha]

Re: Which Ballistic Calculator Is Correct ??

Some calculators might be better than others, but mostly its about understanding their differences in how they handle data input. Terminology varies. My advice is to figure out JBM first (and don't hesitate to ask questions here). Given correct input, it will give you good output. Then, whatever calculator(s) you use can be compared to it.

 

[10ringping]

Re: Which Ballistic Calculator Is Correct ??

I concur. JBM

 

[Muttt]

Re: Which Ballistic Calculator Is Correct ??

I edited my OP to include the date I used.


I do have to acknowledge that JBM is much closer to the data from Exbal. It only works out to be 2 clicks different from Exbal (two more clicks up). And, I was shooting a couple inches low at 545. So, what do 2 (1/4 MOA) clicks work out to be (in inches) at that distance?? At least it's close enough to work it out on the range and edit the information as need be.


You'd think all the programs would use the same math for the same calculations.

 

[Rob01]

Re: Which Ballistic Calculator Is Correct ??

I have been using JBM for years and trust it. The most I have ever been off is .2 mils at 1000 and that's only about 7" which is pretty good for a ballistic calculator.

I use it to run all my charts for matches. I only have a 400 yard range at home so i need a ballistic program i can trust and JBM is it.

 

[Muttt]

Re: Which Ballistic Calculator Is Correct ??

I did a range card for my rifle using the JBM info. It is so close to the Exbal numbers and It's the only one I have access to right now (I'm too cheap to buy one). I also broke it down into clicks at 25 yard intervals. That way, if I know the distance, I can dail for a hit (without doing any math) .... all the way out to 1000.

 

[Trevor300wsm]

Re: Which Ballistic Calculator Is Correct ??

^^^^^
You have your data output listed in "clicks" rather than MOA? Why? Aren't your turrets marked? I'm just curious why you view this as a simpler solution?

On my scope, I could have "40 clicks" or I could have "4 Mils". Why count clicks? Just dial to the number and be done.

 

[pezzy3333]

Re: Which Ballistic Calculator Is Correct ??

Hello,I have a problem with my JBM ballistic calculator.I think that there is something wrong with it because ,when I try to use spindrift calculation I obtain a wrong windage :I shoot with right-hand twist barrel with 22sm rate twist ,when I try to find the windage at 1000m ;wind velocity 2m/s;wind angle 270 degree(a cross wind from left to right)-the JBM gave me a -7clicks to compensate,but when I enter the same wind velocity at angle 90 degree I obtain 18 clicks windage which is immpossible ,because my barrel is right-hand twisted.Please tell me where is the mistake.

 

[turbo54]

Re: Which Ballistic Calculator Is Correct ??

Before anyone EVER scratches their head about a ballistic calculator being off, they MUST perform a full-range scope tracking test. From all tge way down, to all the way up, with several points in between.

No calculator could make my trajectory "jive". I scratched my head for a year. My S&B wasn't tracking. I thiught I was "exempt" from testing, because after all, I had a <span style="font-style: italic"> Schmidt and Bender</span>.

Test your scope.

 

[KYpatriot]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sharp</div><div class="ubbcode-body">Hello,I have a problem with my JBM ballistic calculator.I think that there is something wrong with it because ,when I try to use spindrift calculation I obtain a wrong windage :I shoot with right-hand twist barrel with 22sm rate twist ,when I try to find the windage at 1000m ;wind velocity 2m/s;wind angle 270 degree(a cross wind from left to right)-the JBM gave me a -7clicks to compensate,but when I enter the same wind velocity at angle 90 degree I obtain 18 clicks windage which is immpossible ,because my barrel is right-hand twisted.Please tell me where is the mistake.</div></div>

Take a look at the definitions in JBM . The wind direction in the ballistic FTE App is different in that a 270 wind is right to left, which is backward but there it is.

 

[KYpatriot]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">Before anyone EVER scratches their head about a ballistic calculator being off, they MUST perform a full-range scope tracking test. From all tge way down, to all the way up, with several points in between.

No calculator could make my trajectory "jive". I scratched my head for a year. My S&B wasn't tracking. I thiught I was "exempt" from testing, because after all, I had a <span style="font-style: italic"> Schmidt and Bender</span>.

Test your scope.</div></div>

Best advice on the thread.

 

[pezzy3333]

Re: Which Ballistic Calculator Is Correct ??

Hello,KYpatriot,I checked the definitions in JBM- Wind angles work like this: 0° = headwind, 90° = crosswind (right to left), -90° = crosswind (left to right). You can use any angle, of course, not just these. You can also enter input in O'Clock format; e.g. 3:00 will automatically translate to 90°. Velocity will automatically be adjusted to account for the appropriate headwind calculation. To use O'Clock format in the HUD, set the windage dial format in Settings.
I think that the mistake is somewhere in the settings but I dont know where it is.Please help me.

 

[damoncali]

Re: Which Ballistic Calculator Is Correct ??

In case anyone is wondering, modern ballistic calculators (of which JBM is one) all do use the same math, which is derived from very basic physics. The trouble is that the equations are impossible to solve exactly (at least I'm not aware of anyone who has figured it out).

So we use numerical (in other words, approximate) methods to estimate the solution. These methods do differ between calculators. But two properly written calculators, given the same inputs should return results that are very close to each other. See this post for an example: http://weww.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2509283#Post2509283

If you have large discrepancies between calculators given the same inputs, then it is likely the result of either a) a software bug, b) a poorly written solver, or c) an antiquated method of calculation.

 

[cali_tz]

Re: Which Ballistic Calculator Is Correct ??

Shooter app for smartphones has worked quite well for me. As indicated above it's crucial that you input the right atmo conditions, MVs, BCs, etc...

 

[KYpatriot]

Re: Which Ballistic Calculator Is Correct ??

The results I get from Shooter and BallisticFTE always agree within an inch. I don't anyone could reasonably say one solver is more accurate than another.

I just bought shooter even though I have been happy with FTE. I wanted the Litz values in the shooter database so I didnt have to manually enter them from his book like I have to do with FTE.

The library of standard loads for all kinds of different cartridges is very nice in ballisticFTE, and FTE also allows you more control over the format of the output data. Also, if there isnt a litz value for a certain bullet the FTE app still has BCs that will be a good estimate.

I like the HUD of the shooter app better, and the wind directions are correct instead of reversed like the FTE app.

Like most things on the hide, best answer is to just get both!

 

[KYpatriot]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sharp</div><div class="ubbcode-body">Hello,KYpatriot,I checked the definitions in JBM- Wind angles work like this: 0° = headwind, 90° = crosswind (right to left), -90° = crosswind (left to right). You can use any angle, of course, not just these. You can also enter input in O'Clock format; e.g. 3:00 will automatically translate to 90°. Velocity will automatically be adjusted to account for the appropriate headwind calculation. To use O'Clock format in the HUD, set the windage dial format in Settings.
I think that the mistake is somewhere in the settings but I dont know where it is.Please help me.</div></div>

Sharp, are you talking about using JBM or BallisticFTE? Does JBM have a mobile app for it? If so I have no experience with it. If you can clarify for me what app you are using that will help me help you.

 

[SethBargo]

Re: Which Ballistic Calculator Is Correct ??

I definitely like JBM. My problem is not always having a computer. If you have an Iphone I bought a ballistic calculator that uses the JBM calculator. The name is just simply "Ballistic" and it will say JBM on it. This is well worth the money. It will calculate spin drift and Coriolis for you. It will also set your atmospheric pressures and altitudes. It def is a nice app to have while you are out shooting. Just know it wont be 100% accurate as variables can change. Definitely check it out. And that load your running is almost identical to mine. 42.5gr of RL-15 with 168gr Amax gives me about the same fps.

 

[Muttt]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: trevor300wsm</div><div class="ubbcode-body">^^^^^
You have your data output listed in "clicks" rather than MOA? Why? Aren't your turrets marked? I'm just curious why you view this as a simpler solution?

On my scope, I could have "40 clicks" or I could have "4 Mils". Why count clicks? Just dial to the number and be done. </div></div>


I have my data on my range card in inches, MOA and clicks. Looking back at my post, I did word that kind of silly.


I use Strelok on my smart phone. That program is close. But, I had to tweak the BC slightly (+.003) to get the same numbers I was getting with JBM. Still not sure which is actaully correct. Still waiting to get a chance to get out to 600, 800 and 1000 to work out the actual numbers. Then, which ever ballistic calculator hits the actual numbers ..... wins.

 

[hrt4me]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">I have been using JBM for years and trust it. The most I have ever been off is .2 mils at 1000 and that's only about 7" which is pretty good for a ballistic calculator.

I use it to run all my charts for matches. I only have a 400 yard range at home so i need a ballistic program i can trust and JBM is it.</div></div>

I have also had good results with JBM during the course of the past decade

 

[wadebrown]

Re: Which Ballistic Calculator Is Correct ??

I use JBM on my laptop or Shooter on my Android and when I was developing ballistics applications for military systems, I always checked them against JBM when I matched JBM's results I knew I had achieved the best accuracy I could. When I shoot I make the same assumptions, JBM gives me the best estimate on the bullet's trajectory, if I hold up my end of the bargain and give it the correct inputs. I have competed with brand new guns that I only had a 100 yard zero and JBM gave me a good enough estimate that in two sighters I was in the X-ring, at 600 yards. I tell shooters that tell me JBM is not accurate for their gun that their muzzle velocity is not correct and usually when they shoot it over another chrony they come to the same conclusion.

The poster who said we all use the same starting point is generally true, most start from the modified point mass equation written up in McCoy's book but there is a lot of room for error before you get to the final result.

Just my two cents,

wade

 

[RobertB]

Re: Which Ballistic Calculator Is Correct ??

I use a program to get me close, then go out to the range and set up a square known distance target system, mine I have steel at 4,5,6,7,amd 750 yds. with 1" dot for reference. I shoot each target recording my dope applied to the scope (after verifing a 100 yd zero.) then go to each target and see what its doing. Then I make the adjustments to get center mass hits at each range. Record those numbers,Then juggle numbers (B.C., velocity, maybe DA) until it matches. THat works for me. You can print a drop chart out go shoot and with one target you can tune it to fit much better than just running the numbers from my luck. Learned this from TVP where they had a great fast system. Berm at 600 yds and 1000 yds with clay piegeons on the berm. Verify zero, get dope at 600 amd 1000 yds. Juggle numbers on ballistic calculater to match, have pretty accurate chart with maybe 10 rds downrange. Good luck

 

[RobertB]

Re: Which Ballistic Calculator Is Correct ??

Fine tuning never ceases though I might add.

 

[Ultraman550]

Re: Which Ballistic Calculator Is Correct ??

I have Ballisic and Shooter and the one thing I love about Shooter is the velocity calibration that allows you to enter up to 5 target distances and your actual sight distances. It completely resets the program to what you actually get during range time and becomes an accurate application for those that are having trouble.

 

[jbmillard]

Re: Which Ballistic Calculator Is Correct ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: damoncali</div><div class="ubbcode-body">In case anyone is wondering, modern ballistic calculators (of which JBM is one) all do use the same math, which is derived from very basic physics. The trouble is that the equations are impossible to solve exactly (at least I'm not aware of anyone who has figured it out).

So we use numerical (in other words, approximate) methods to estimate the solution. These methods do differ between calculators. But two properly written calculators, given the same inputs should return results that are very close to each other. See this post for an example: http://weww.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2509283#Post2509283

If you have large discrepancies between calculators given the same inputs, then it is likely the result of either a) a software bug, b) a poorly written solver, or c) an antiquated method of calculation. </div></div>

Generally, the equations (in my solvers anyway) are solved to good accuracy like 4 to 5 decimal places. You can higher, but there's not need. The problem that I've seen when people ask me to look at their solutions is that they are using the wrong kinds of algorithms to do the numerical integration. The GNU ballistics solver was extraordinarily bad when I looked at it a few years ago. Then there's the question of inputs like what they use for a gravitation acceleration, atmospheric density, etc. These values will lead to very slight differences in the output. I have found that if you use the exact same inputs and have a pretty decent numerical solver, you get the same outputs.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The poster who said we all use the same starting point is generally true, most start from the modified point mass equation written up in McCoy's book but there is a lot of room for error before you get to the final result.
</div></div>

Actually most start from the Point Mass equations. There are only two modified point mass solvers that I know of outside of the military. The problem is the manufacturers don't/can't get the required coefficients to do a modified point mass. There really isn't any need either.

Brad