Ballistics Data - GIGO

MDof2

MDof2

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I was taught long ago, Garbage In Garbage Out. Applies to ballistics calculators, life, business, alcohol, I digress.

When working up a match or putting together ranges and come ups, who's data do you rely on most? (providing you don't have specific DOPE already)

1. Kestrel with AB solution solver along with the bullet database in the AP software?
2. Strelok which is pretty well populated in cartridge and bullet data along with the with G1/G7 drag models.
3. Manufactures BC data for specific bullets then input into something like Ballistics Buddy, JBM, or Strelok Pro (manual mode) which you input into your chosen solver?

Here's the issue I'm having / a specific example:
Once in a while the data in from different sources isn't always the same. My Kestrel with the AB software shows a BC for the Hornady 140g ELD of 0.568. However Hornady states the BC for their bullet is 0.646, which is also what Strelok Pro uses.
At close range the numbers are negligible as far as getting on target. The difference in data obviously gets greater the further you go.

So which garbage goes in?
 
MDof2 said:
I was taught long ago, Garbage In Garbage Out. Applies to ballistics calculators, life, business, alcohol, I digress.

When working up a match or putting together ranges and come ups, who's data do you rely on most? (providing you don't have specific DOPE already)

1. Kestrel with AB solution solver along with the bullet database in the AP software?
2. Strelok which is pretty well populated in cartridge and bullet data along with the with G1/G7 drag models.
3. Manufactures BC data for specific bullets then input into something like Ballistics Buddy, JBM, or Strelok Pro (manual mode) which you input into your chosen solver?

Here's the issue I'm having / a specific example:
Once in a while the data in from different sources isn't always the same. My Kestrel with the AB software shows a BC for the Hornady 140g ELD of 0.568. However Hornady states the BC for their bullet is 0.646, which is also what Strelok Pro uses.
At close range the numbers are negligible as far as getting on target. The difference in data obviously gets greater the further you go.

So which garbage goes in?
Click to expand...

Don't put any garbage in and there won't be any garbage out. If there's a disparity, do two separate calculations that are identical with the exception of the BC, and whichever one gets you the better result is the better data.

You might find this relevant and interesting...

https://www.hornady.com/support/ballistic-coefficient
 
Maybe I need to relearn calculators and ballistics apps then for longer range engagements because I'm pulling my hair out over the "garbage out" end where I triple check data going in to be absolutely the same, but still get different numbers out.
I'm going dizzy trying to sort it out if I'm doing something wrong, or what. Or am I splitting hairs between the difference of 7.25 vs 7.4 or 7.3. I can't outshoot 7.25 versus 7.4 at 950 yards, but math is math, no?

For example:
6.5CM
2.4" Sight Height
1:8 twist
Zero @ 100 yds
80* / 29.5bp / 65%rh
Caliber: 6.5CM
Hornady 140G ELD Match
BC 0.326 - G7
2760 fps

Target at 950 yards

Here's what I get back and I'm not sure why.
Hornady: 7.2
Kestrel: 7.31 mil
Shooter: 7.3mil
Strelok Pro: 7.4mil
JBM: 7.4
Ballistics Buddy 7.4mil
 
Last edited:
MDof2 said:
Maybe I need to relearn calculators and ballistics apps then for longer range engagements because I'm pulling my hair out over the "garbage out" end where I triple check data going in to be absolutely the same, but still get different numbers out.
I'm going dizzy trying to sort it out if I'm doing something wrong, or what. Or am I splitting hairs between the difference of 7.25 vs 7.4 or 7.3. I can't outshoot 7.25 versus 7.4 at 950 yards, but math is math, no?

For example:
6.5CM
2.4" Sight Height
1:8 twist
Zero @ 100 yds
80* / 29.5bp / 65%rh
Caliber: 6.5CM
Hornady 140G ELD Match
BC 0.326 - G7
2760 fps

Target at 950 yards

Here's what I get back and I'm not sure why.
Hornady: 7.2
Kestrel: 7.31 mil
Shooter: 7.3mil
Strelok Pro: 7.4mil
JBM: 7.4
Ballistics Buddy 7.4mil
Click to expand...

The inner workings of all those calculators are not the same, there's undoubtedly some differences between how many decimal places are figured in, programming considerations, and whatever else. What's critical is what works best. I rely on my Kestrel over the Strelok app for instance, because the Kestrel has given me more reliable results. If I only had Strelok to use though, I'd have no problem doing so, it got me through until I could buy the Kestrel.
 
Matt.Cross said:
The inner workings of all those calculators are not the same, there's undoubtedly some differences between how many decimal places are figured in, programming considerations, and whatever else. What's critical is what works best. I rely on my Kestrel over the Strelok app for instance, because the Kestrel has given me more reliable results. If I only had Strelok to use though, I'd have no problem doing so, it got me through until I could buy the Kestrel.
Click to expand...
I appreciate the insight. I think I'm learning from this I need to remember a few key points here.
What's critical is what works best
Black Magic under the hood spread across a decimal place.
Stay on target.

What brings me to this point is I've used Strelok Pro for some time with good results. Darn good results. Trued when needed from crono numbers or POI down range. Works excellent.
I recently bought the Kestrel so starting to / wanting to carry less to matches, ranges, etc. and use one device that does multiple tricks, environment, ballistics, smaller footprint, lot less screen to break than a smartphone, etc.
So when playing with numbers across various calculators, and then plugging them into my Kestrel, I start pulling my hair out.
 
Are you using "advertised" FPS values, or are you using "actual" FPS values for the ammo from a chrono?
 
Last edited:
MDof2 said:
I appreciate the insight. I think I'm learning from this I need to remember a few key points here.
What's critical is what works best
Black Magic under the hood spread across a decimal place.
Stay on target.

What brings me to this point is I've used Strelok Pro for some time with good results. Darn good results. Trued when needed from crono numbers or POI down range. Works excellent.
I recently bought the Kestrel so starting to / wanting to carry less to matches, ranges, etc. and use one device that does multiple tricks, environment, ballistics, smaller footprint, lot less screen to break than a smartphone, etc.
So when playing with numbers across various calculators, and then plugging them into my Kestrel, I start pulling my hair out.
Click to expand...

Strelok can give you a better MV number than a chrono can, use your trued MV from Strelok and feed that to the Kestrel, after that I would trust the Kestrel.
 
Applied ballistics comes back at 7.4 using your data above.

Dial 7.3 send it and see?
 
And for the record, I'm 100% accepting of the fact I'm fvcking something up when inputting data and variables.
Being married 20 years.... I know how to not follow instructions.

Appreciate the feedback, ya'll.
 
A .2 variance across 7 different calculators doesnt sound all that terrible to me. Of course that's kind of a difference of about what 14 inches give or take?

I also entered your data manually without weather or elevation. It will be interesting to see which one is closer from the start.
 
And I think that's what I'm getting tangled up on. Atmosphere variables across calculators, and then comparison to the Kestrel either taking live or locked weather variables.

And yes, agreed, .2 is an amount that I'll never outshoot at 950yds. I was driving my thought process in the OP from a math standpoint across different solvers.
 
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