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Ballistic Apps

Buttermilk

Buttermilk

Well-Known Member
Joined
Dec 19, 2005
Messages
1,217
Location
Good Ol' Oklahoma
Currently I use Shooter and Hornady 4DOF.

When both are fed the same inputs, they both put out the same data.

Recently, I've found a place to shoot ~400-420 yds or so. My guns are zero'd at 100 yds.

What I've noticed is that I am repeatedly impacting high on the target after dialing up. Typically 1/2 to 1 MOA difference in impact vs dialed. As an example, my Shooter app may say to dial up 5.5 MOA but actually 4.5 MOA gets the bullet close to point of aim.

So far, everything we've shot (myself, my brother and a friend) have all been high on impact. The closest one yet was my 30 Nosler #1, which impacted only 2" high at 406 yds.

This includes a 6mm ARC, 300 RUM, 30 Nosler, 300 WM, 28 Nosler.

My brother's 300 RUM was calling for 4.5 MOA up. Reality was it only needed 4 MOA up.

The 6mm ARC was calling for 5.5 MOA up, but only needed 5 MOA.

A 300 Win Mag called for 5.5 MOA up but only needed 4.5 MOA up.

I've looked closing at my data inputs, and scratching my head as to why. Everything seems correct. Conditions are input correctly, Gun specifics are correct, load fps is as accurate as my Chrony can be.

I even make sure my actual zero is input correctly as well, as both Shooter & H4DOF allow that.

I'm certain I'm doing something wrong, just not sure what. 🤷‍♂️

If I do the velocity calibration for the 300 WM for example, it says I'm pushing a Berger 190 VLDH at 3273 fps which is insane. Chrony shows 3093 fps average for the load from a 26" barrel.

At 400 yds it's still off a bit, and at farther distances would only get worse.
 
I haven't used either extensively, but from what I remember 4DOF doesn't correct for atmosphere unless you have an external weather meter hooked up. That'll have a pretty big impact on your results. You could get a simple weather meter like a Kestrel Drop to get environmentals into your app.

If you want something more accurate buy a Kestrel 5700. Once you do the MV tuning and get a handful of temperatures/velocity entries it'll be dead on.
 
biednick said:
I haven't used either extensively, but from what I remember 4DOF doesn't correct for atmosphere unless you have an external weather meter hooked up. That'll have a pretty big impact on your results. You could get a simple weather meter like a Kestrel Drop to get environmentals into your app.

If you want something more accurate buy a Kestrel 5700. Once you do the MV tuning and get a handful of temperatures/velocity entries it'll be dead on.
Click to expand...
It allows the user to manually input the conditions which I've done. Don't see how the kestrel would be any more accurate since it's gonna use either AB (same as Shooter) or H4DOF for the math.

I'm certain I'm missing something simple. Just have not caught it yet.
 
Some of the stuff we look at is
scopes being calibrated and info imputed into programs
speed measured by lab or magneto is fact then don't fudge the speed but tweak the BC because science proved your speed and your barrels machining or tooling in the groves affects and distorts the bullets BC for what its rated for - your barrel and your speed is easily different from the manufacturers setup, speeds and ratings.

Just a few
JH
 
Buttermilk said:
It allows the user to manually input the conditions which I've done. Don't see how the kestrel would be any more accurate since it's gonna use either AB (same as Shooter) or H4DOF for the math.

I'm certain I'm missing something simple. Just have not caught it yet.
Click to expand...
A Kestrel (or any other weather meter) give you real time environmentals for your location. If you're manually entering values from an external weather meter you're probably good to go there. If you're using values from a nearby weather station or your phone's internal sensors you're not getting accurate values for your particular location. Depending on which version you get you can get more accurate drag models than normal G1/G7 BCs, though you probably won't see a difference inside of 1000yd. The temperature/MV compensation is big if you run into big temperature swings, even with relatively temperature stable powders.

It could just be the BC of your bullet. There's a lot of factors that affect BC, and in many cases your real world BC will be lower than what's listed on the box. If you get accurate drops after doing the MV calibration don't sweat it. You could screw with BC until you get accurate drops, but you're just putting more effort into achieving the same thing MV calibration does.
 
I don't know your experience level with apps etc and external ballistics but generally apps like Shooter, AB, etc are very accurate. The keys are rifle and ammo profile with a solid set of environmental data. Generally with Apps I see the common mistake of using the atmospheric section wrong. Some will run station pressure from a local source, which is fine if its very near your location. Others will use the elevation and barometric pressure in Absolute vs corrected. This is a problem. When using absolute, you DO NOT enter elevation. The last method is to use Desnsity Altitude (DA). DA is one stop shop of temp, elevation, baro, and humidity. If you have a kestrel or similar device you can set the app to DA and the meter to DA and use a singular input. In some cases you can blue tooth the data, kestrel 5700 for example.

In the end, IMHO, you are seeing high impacts because the app is not set up right for atmospheric. Another issue that can occur for a range shooter and heat is, mirage. The target boils up and to the shooter that means the target appears high, therefore, you aim higher and impact higher.
 
The apps will get you really close but nothing will take the place of actually shooting the rifle at known distances and making adjustments to the formula. Way to many variables go into shooting at distances to make it an exact science but the apps will get you really close.We shoot to 600 on a fairly regular basis on one of our local ranges. The apps get us on the steel (12 x 12) but its not always right in the center. Usually really close to 400 then starts to vary a little. We make the necessary adjustments to the program to get us on center and then print the charts.
Good Luck
 

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