Ballistic apps and potential energy via gravity

[Stubbers]

The free Hornady app seems OK for level shots. Which is what most people are doing. And I like that it appears to be taking into account the difference between shooting up versus down. But outside of that, the math for their inclination compensation is flawed.


The Hornady app is not a good model to use for testing the original question that I posed in this thread.

You're either contradicting yourself here or I do not follow, either way I have no desire to entertain the argument. The reason I brought the Hornady app into this thread is because it DID show the difference you're posing, which is the effect that gravity has based on - or + inclination angle...simple as that. The app answered your question, as well as the real world data I presented from Sierra.

You should post your issues with the App on google/apple store reviews.

-Matt

 

[Scotchmo]

You're either contradicting yourself here or I do not follow, either way I have no desire to entertain the argument….

You might not follow what I was saying.

Yes, the Hornady app gets good reviews.

Most people shoot horizontal and the Hornady app does fine for that, so the good reviews in that case are valid.

We are talking about angled shots for which the Hornady handles incorrectly. So I can’t trust its predictions in those instances, regardless of whether it shows a difference between up and down.

I’m not invested enough with the Hornady app to get involved with trying to get them to fix it.

But I do appreciate that you brought up the Hornady app as an example, because, so far, it’s the only one that appears to acknowledge the up/down difference in its calculations.

So the new question for anyone else that cares to entertain it: Is there an app that does the inclination math correctly while also taking into account a difference between an upward and downward shot?

 

[Stubbers]

You might not follow what I was saying.

Yes, the Hornady app gets good reviews.

Most people shoot horizontal and the Hornady app does fine for that, so the good reviews in that case are valid.

We are talking about angled shots for which the Hornady handles incorrectly. So I can’t trust its predictions in those instances, regardless of whether it shows a difference between up and down.

I’m not invested enough with the Hornady app to get involved with trying to get them to fix it.

But I do appreciate that you brought up the Hornady app as an example, because, so far, it’s the only one that appears to acknowledge the up/down difference in its calculations.

So the new question for anyone else that cares to entertain it: Is there an app that does the inclination math correctly while also taking into account a difference between an upward and downward shot?

I never suggested to use Hornday brother.

I merely introduced it into this thread as an answer to your question, that yes, gravity does effect the incline or decline angle. If you have issues with Hornday's app, you should write a review to them OR to their devs to correct the issue you claim. I wouldn't even advise using it though unless using their ammo...All the information I see is correct and based on other forums / data they're data is quite correct.

NOTHING will beat a dope card...these ballistic apps are used as approximations to help you get close.

I am unaware of any *free* ballistic apps that will do as you ask other than what I already mentioned. Good luck.

-Matt

 

[Stubbers]

Oh, and I e-mailed Igor from Sterlok on this matter on your behalf...to see if he'd consider adding such effects.

-Matt

 

[Stubbers]

Igor is quick to answer but I don't think he is to eager to do major changes to the app. A few years back I suggested / requested some practical additions and he said he will look into but nothing happened. I don't know if and what changed since he was sanctioned as I still use the last version before that.

Worth a shot, e-mail takes a few seconds. Hopefully Scott can find an app that is well rounded like Sterlok but includes what he wants.

Maybe look into Applied Ballistics documentation, its a $29.99 app IIRC...but I am sure there has to be documentation that states what it does.

https://appliedballisticsllc.com/wp-content/uploads/2019/11/ABMobileUserGuide.pdf

-Matt

 

[Scotchmo]

Oh, and I e-mailed Igor from Sterlok on this matter on your behalf...to see if he'd consider adding such effects.

-Matt

I appreciate that, as I am invested (time and use) in Strelok. Unfortunately, I’m currently using an iPhone so I do not have access to any updates of Strelok. Though I continue to use Strelok with the hopes that updates will be more readily available in the USA in the future.

Strelok has some other minor data errors that I’d like to see fixed as well. It’s internal data is done in meters, but when displaying yards, internally it rounds (always up) to the meter. That causes some impossible results. Small but minor errors that bug me none the less.

As I said, I’m not going to put any time into trying to get Hornady to fix their app. I’d rather stick with Strelok, especially if Igor continues to update it. And I’ll switch to a Samsung device if that means I can get updated Strelok versions.

 

[Stubbers]

I appreciate that, as I am invested (time and use) in Strelok. Unfortunately, I’m currently using an iPhone so I do not have access to any updates of Strelok. Though I continue to use Strelok with the hopes that updates will be more readily available in the USA in the future.

Strelok has some other minor data errors that I’d like to see fixed as well. It’s internal data is done in meters, but when displaying yards, internally it rounds (always up) to the meter. That causes some impossible results. Small but minor errors that bug me none the less.

As I said, I’m not going to put any time into trying to get Hornady to fix their app. I’d rather stick with Strelok, especially if Igor continues to update it. And I’ll switch to a Samsung device if that means I can get updated Strelok versions.

Hornday is to prove the effect. You could also just use its data as reference on your +/- angle difference provided you put in your inputs correctly. ..something is better than nothing.

If you're looking for a ballistic app with 0 errors, we're not quite there yet, you'll need to make custom dope cards.

-Matt

 

[Scotchmo]

I use an Android phone but the only way to "update" is to buy a new copy from the Huawei site. Since most of his update of late was additions of reticles and ammo I am not to eager to update. What is in the app now works for me together with the other apps I have. I only use it occasionally anyway.

I see a lot of new reticle requests on the Strelok Facebook page. I don’t really care about reticles as I only need the numerical data for compensation.

I use Strelok a LOT!

I have a Bluetooth MTC rangefinder, Bluetooth Kestrel weather station, and a Bluetooth anemometer, all purchased because they communicate with Strelok. The real time compensation adjustments in Strelok are valuable when shooting long distance. I don’t really want to give those up if switching to another app. I don’t mind purchasing Strelok again.

 

[steve123]

Aside from the ballistic apps and angles I've experienced some crazy vertical problems when shooting long range with very precise centerfires.
I would use a Kestrel and DA/Density Altitude.

My friends shooting range is up on a hill around 7 degrees from a steel Ram I was shooting 550 yards away. The wind was coming in to me at 20-25 ish mph. I normally hit this Ram no problem because it's a easy target. We're talking a 6mm 105gr/G1BC of .545 at 3120 fps. After missing high a half dozen shots I measured the misses to be averaging .5 mils high. I was shocked! So much so I couldn't resist going back later in the week in normal winds to try again only to have my dope right on as usual.
The only conclusion that made sense to me was that this topography combined with wind pressure pushed the bullets up when the wind hit the hill.

I also had what must have also been wind affecting vertical at our AZPRC long range centerfire matches which was high above the valley below where the steel was. We knew the distances were correct because my engineer friend used a fancy GPS unit he had for his work that supposedly was precise to 10mm. If it was windy we could see the difference between our dope and how much compensation vertically we'd need to hit the steel.

Airgun related, our FT club had some targets at steep angles down into a gravel pit. I could compensate pretty closely for the angle when it was calmish but the pellet was going crazy in the vertical when it was windy. People already knew to aim lower because of the down angle but the patterns of misses on the faceplate when it was windy proved that the topography was pushing the pellet way way up. Say at 55Y to make a hit one would need to aim a half inch below the KZ and 2.5"-3" off of it vs the normal lower half of the KZ and a 1/4" out of the KZ.

And shooting my Vulcan 3 using Altaros slugs when it's windy but this time shooting uphill at 13 degrees on windy days at 300Y I notice the vertical fall apart as well. The vertical can be almost twice what it is on calm days.

All can be pretty frustrating, lol.

 

[Stubbers]

I just checked, and GeoBallistics ALSO calculates this effect and is free to try but pro cost 15$. Works with Kestrel Weather Station and WeatherFlow.

I entered in the same Data as the above Real world test, and it actually is closer than Hornday @ .4"~ predicted difference from 1300 fps 240 gr @ -15/+15....

If you have YOUR slug information from BC (G1 or G7), Diameter, Length, and Muzzle velocity, and weight, I can see what it spits out @ +15 and -15 for you.

-Matt

 

[Scotchmo]

Aside from the ballistic apps and angles I've experienced some crazy vertical problems when shooting long range with very precise centerfires.
I would use a Kestrel and DA/Density Altitude.

My friends shooting range is up on a hill around 7 degrees from a steel Ram I was shooting 550 yards away. The wind was coming in to me at 20-25 ish mph. I normally hit this Ram no problem because it's a easy target. We're talking a 6mm 105gr/G1BC of .545 at 3120 fps. After missing high a half dozen shots I measured the misses to be averaging .5 mils high. I was shocked! So much so I couldn't resist going back later in the week in normal winds to try again only to have my dope right on as usual.
The only conclusion that made sense to me was that this topography combined with wind pressure pushed the bullets up when the wind hit the hill.

I also had what must have also been wind affecting vertical at our AZPRC long range centerfire matches which was high above the valley below where the steel was. We knew the distances were correct because my engineer friend used a fancy GPS unit he had for his work that supposedly was precise to 10mm. If it was windy we could see the difference between our dope and how much compensation vertically we'd need to hit the steel.

Airgun related, our FT club had some targets at steep angles down into a gravel pit. I could compensate pretty closely for the angle when it was calmish but the pellet was going crazy in the vertical when it was windy. People already knew to aim lower because of the down angle but the patterns of misses on the faceplate when it was windy proved that the topography was pushing the pellet way way up. Say at 55Y to make a hit one would need to aim a half inch below the KZ and 2.5"-3" off of it vs the normal lower half of the KZ and a 1/4" out of the KZ.

And shooting my Vulcan 3 using Altaros slugs when it's windy but this time shooting uphill at 13 degrees on windy days at 300Y I notice the vertical fall apart as well. The vertical can be almost twice what it is on calm days.

All can be pretty frustrating, lol.

I’m not sure if Strelok correctly takes into account the lift or depression on projectiles when shooting at high angles into or away from a horizontal head wind/tail wind/quartering wind. That’s a whole other issue.

 

[Scotchmo]

I just checked, and GeoBallistics ALSO calculates this effect and is free to try but pro cost 15$. Works with Kestrel Weather Station and WeatherFlow.

I entered in the same Data as the above Real world test, and it actually is closer than Hornday @ .4"~ predicted difference from 1300 fps 240 gr @ -15/+15....

If you have YOUR slug information from BC (G1 or G7), Diameter, Length, and Muzzle velocity, and weight, I can see what it spits out @ +15 and -15 for you.

-Matt

Thanks Matt,

I already put it into the Hornady app, and for horizontal shots, it is close to Strelok and real world. But the 15 degree angle shots are way low for the needed compensation at 600yds.

Even though the overall compensation shows low, the difference between up and down in the Hornady app looks to be about what I would expect, so I could use that to adjust the compensation that I get from Strelok. But that’s one more thing I’d rather not have to do in the moment.

Here is MY slug information for the current highest BC airgun projectile that I use:
G7 BC=0.182
.307” at max diameter (driving band)
1.078” long
1010fps
171gr

 

[Stubbers]

Thanks Matt,

I already put it into the Hornady app, and for horizontal shots, it is close to Strelok and real world. But the 15 degree angle shots are way low for the needed compensation at 600yds.

Even though the overall compensation shows low, the difference between up and down in the Hornady app looks to be about what I would expect, so I could use that to adjust the compensation that I get from Strelok. But that’s one more thing I’d rather not have to do in the moment.

Here is MY slug information for the current highest BC airgun projectile that I use:
G7 BC=0.182
.307” at max diameter (driving band)
1.078” long
1010fps
171gr

Geoballistic shows 23.8" or 1.1 mrad predicted difference at 600 yards, assuming 100 yard zero.

-Matt

 

[Stubbers]

Using the same data in Hornady, it shows 24.7" difference between -15 or + 15 at 600 yards with 100 yard zero.

Seems both calculators are really close...within 1"...and there could be a small discrepancy due the rounding of mrad to the 1st decimal.

Also Hornady can pair with weather meters as well via bluetooth, just as Geoballistics and Sterlok.

239 VS 222 FPE @ target shown via Geoballistics
242 VS 227 FPE @ target shown via Hornady

-Matt

 

[Scotchmo]

Geoballistic shows 23.76" or 1.1 mrad predicted difference at 600 yards, assuming 100 yard zero.

-Matt

40 yd zero
82F
28.74 inHg
55% humidity
600yds

Strelok
-15 degrees, 99.7 moa
0 degrees, 103.7 moa
+15 degrees, 99.7 moa

Hornady
-15 degrees, 91.01 moa
0 degrees, 103.65 moa
+15 degrees, 95.14 moa

I think the difference between the 91 and 95 Hornady values might be about right, but they are way too low to be on target. Strelok does not differentiate between + or - 15 degrees, but the 99.7 value gets me close and sometimes on target.

What are the MOA compensation values for Geoballistics?

 

[Stubbers]

Geoballistic, assuming 1.75" scope height.

-15 = 99.3 moa
0 = 105 moa
+15 = 103 moa

-Matt

 

[Scotchmo]

Geoballistic, assuming 1.75" scope height.

-15 = 99.3 moa
0 = 105 moa
+15 = 103 moa

-Matt

2.76” is the scope height. Even so, the Geoballistics predictions look pretty good. A lot better than Hornady.

 

[Stubbers]

2.76” is the scope height. Even so, the Geoballistics predictions look pretty good. A lot better than Hornady.

Going from 1.75" to your 2.76" with Geoballistic (found where I can let it round to 2nd decimal vs 1st)

-15 = 97.03 MOA
0 = 102.78 MOA
+15 = 100.75 MOA

 

[Stubbers]

Igor replied to my request and said "I will think how it can be done"....because (in my opinion) integrating such effects is not straightforward and the current apps that achieve this calculation probably relied on Doppler data to work out a expression or equation that lines up with their data. Wish I had the answers for him because it's not that he isn't willing, rather the solution isn't known or widespread knowledge, and heck, I'd like to integrate it into my personal one but...math is hard.

-Matt

 

[Scotchmo]

Igor replied to my request and said "I will think how it can be done"....because (in my opinion) integrating such effects is not straightforward and the current apps that achieve this calculation probably relied on Doppler data to work out a expression or equation that lines up with their data. Wish I had the answers for him because it's not that he isn't willing, rather the solution isn't known or widespread knowledge, and heck, I'd like to integrate it into my personal one but...math is hard.

-Matt

I don’t see why it would take a Doppler data.

There is a gain or loss in projectile energy as the target elevation is raised or lowered. Very easy to calculate that. Since I would be hard pressed to do the analytics, I would be using numerical integration, probably every inch (or cm).

Over the entire distance of 600yds, when compared to a level shot, the 171gr projectile loses about 11.4 additional FPE on a +15 degree shot and gains that amount on a -15 degree shot. Those losses or gains can be factored in incrementally along the trajectory path, and the corresponding velocity adjusted accordingly.

There is also the air density changes that must be accounted for as the projectile rises or falls. That can also be accounted for incrementally via numerical integration.

It’s not an exact solution, but probably better than ignoring it.