Getting to know the Shooter ballistics app.
Note: This article is still being developed. Judge accordingly...
The Shooter ballistics application is a powerful ballistics calculator for mobile devices . It is a very useful tool at a bargain price. It is used during our training classes to create commonality amongst our students and this article is offered as a way to get started with using the app before our classes.
The app Shooter can be found in the App Store or Play Store from your mobile device. Once the app is downloaded and opened, the following information should get the rifleman off to a good start on setting preferences and creating a profile for the rifle and ammunition.
As with all computing, "garbage in equals garbage out" holds true. The app will give you a solution no matter what inputs you give it. It is important to understand what the inputs are and how they relate to your particular rifle. The Shooter manual linked at the bottom of the article has a great write up on what each parameter is. Inputting environmental conditions is as important as knowing which bullet you shoot. If you are shooting in Wyoming but your app still thinks you are at home in Texas, you are likely going to miss your target. With a data signal to the device, atmospheric conditions can be downloaded within the Shooter app from a nearby weather station, likely an airport. In many cases in the western landscape, the closest weather station may be many miles away. This data is better than what your app remembers from your last shooting session, but getting data for your AO from a handheld weather meter, such as a Kestrel, is far better. You can input this weather data manually or possibly take advantage of a Bluetooth connection between the mobile device and the weather meter. Setting up this connection takes some reading in the weather meter manual and Shooter reference materials.
Using environmental data from the weather station or hand held meter necessitates an understanding of how the air pressure is reported. Air pressure is reported as either Station Pressure or Barometric Pressure. Station Pressure is an absolute pressure, while Barometric Pressure has been referenced to sea level conditions. Using Barometric pressure for ballistics requires knowing the altitude on site. Station pressure is a better input to ballistics calculators because knowing the altitude is not necessary. A further explanation is available on the Applied Ballistics site, available at the link at the bottom of the article. The important part of this air pressure discussion is knowing what you have and telling the calculator what you are using. Android: If using Station Pressure from your Kestrel handheld weather meter, you need to tell the Shooter app that "pressure is absolute" in the preferences.
Density Altitude (DA) is another parameter to study. In short, DA is a parameter that is a combination of air pressure, temperature, and relative humidity. Using DA makes communications cleaner and less prone to error as we only have one input instead of three if entering data manually. It is recommended to select "Use Density Altitude" in the preferences. DA can be thought of as the air density factor that the bullet sees.
After downloading and starting the app, a good first step is to set up the options in the preferences. For iPhone users, access the app preferences by tapping on the iPhone "settings" app and scroll down to and tap on the Shooter app in the list. Android users have access to the settings screen from within the Shooter app by tapping on the menu button on the upper right hand corner of the main screen.
Recommended preference setting changes from default:
Save Last Inputs - ON - remembers your data from the previous time running the app which may have been a couple minutes ago prior to taking that selfie
Use Density ?Altitude - ON
Automatic Atmosphere Enabled - OFF - you would rather have the weather from your weather meter rather from the previous shot instead of more recently loaded data from the airport back in town
Populate Wind - OFF - who cares what the wind is doing at the weather station or even in your hand held meter, you need to think about the wind the bullet is going to see and enter that.
Distance Step size (trajectory table) - 10 - a good distance to show in the table to start with, change for your needs
The preferences parameters can be investigated in the Shooter manual linked at the bottom of this article.
To build a profile for our "Sawtooth Demo1" rifle and the 6.5 Creedmoor Hornady ammunition, follow these steps
1. Add a firearm
Android: Tap "+" to add a firearm
iPhone: Tap ">" next to Firearm to add a firearms
2. Enter "Sawtooth Demo1 6.5 Creedmoor" as the rifle name, then continue with the following properties and save the rifle profile. Keep this rifle saved on your list for use in our classes.
Barrel Twist = 1:8"
Twist Direction = Right
Sight Height = 2.2"
Sight Offset = 0
Elevation Unit = Mils
Elevation Turret Grad = 1/10
Windage Unit = Mils
Elevation Turret Grad = 1/10
Lead Unit = Mils
Elevation Correction Factor = 1.0
Windage Correction Factor = 1.0
Android: Rifle parameters entered, tap disk to save.
iPhone: Tap + to add a firearm.
iPhone: Enter the Rifle parameters and tap Save
3. Add an ammunition profile to the firearm.
Android: Tap + to add an ammunition profile to the firearm.
iPhone: Tap the arrow next to Ammunition.
4. Select "Manually" then enter "140 ELD-Match Hornaday" as the bullet name and continue with the following properties. Save the bullet profile.
Bullet Diameter = .264 in
Bullet Weight = 140 gr
Bullet Length = 1.38 in
Muzzle Velocity = 2780 fps
MV Variation = (leave blank)
Powder Temp = (leave blank)
Atmosphere Std. = ICAO
Drag Model = G7
BC .326 Min Velocity 2512
BC .320 Min Velocity 2232
BC .310 Min Velocity 0
BC Note, to add rows to the BC listing, tap the green + symbol. To delete a row, tap the red X symbol on the desired row.
Zero Range = 100 yd
Zero Height = 0
Zero Offset = 0
Enable Zero Atmosphere = do not check
Android: First half of ammunition input screen.
iPhone: Ammunition input screen. Enter data and tap Save.
Android: Bottom half of ammunition input screen. Tap File icon in upper right to save the profile.
5. Select the ammunition.
Android: Tap on the ammunition listed.
iPhone: Tap on the ammunition listed.
6. Enter field and atmospheric conditions, then calculate a solution.
Android: Enter Environmental conditions then tap the arrow in the upper right to calculate a shooting solution. Then next screen will depend on your settings but you can toggle through the chart, graph, and heads up display.
iPhone: Enter Environmental conditions then tap Calculate to create a shooting solution.
In the solution mode, the solution can be viewed as a heads up display (HUD), chart, or graph. You can toggle between the views and each view has a menu option. Explore the menu to see the capabilities of the calculator. In the HUD, the menu opens a Range Calculator (calculator to calculate distance to targe based on target size and an angular measurement taken with the reticle), a tool to find the look angle using the devices sensors, and the option to switch between wind and lead inputs. In the table view, the menu includes the option to switch between showing wind drift and lead, as well as a feature to send the chart as an email. In the graph view, the menu allows to toggle between bullet path and wind drift. There is also a button that allows comparing bullets by adding multiples to the graph. The compared bullets have to be under the same firearm (a "shooter hack" for comparing different cartridges is shown later).
Android: Solution HUD. Tap the menu button at upper right for options.
iPhone: Solution HUD. Tap the menu button at upper right for options.
Android: Solution Table. Tap the menu button at upper right for options.
iPhone: Solution Table. Tap the menu button at upper right for options.
Android: Solution graph. Tap the menu button at upper right for options, and the compare button to the left of the menu button, to add additional projectiles to the graph.
iPhone: Solution graph. Tap the menu button at upper right for options and to add projectiles to compare.
To edit a profile for a firearm or ammunition
Android: tap and hold on the listing to bring up an edit or delete option.
iPhone: slide left on the listing to expose an edit or delete option.
In the shooting solution view, toggle between Table, Chart, and Heads up Display by:
Android: slide left or right on the current pane. In the chart pane, you can slide up or down if it fills more than the screen.
iPhone: tap the title in the selection pane at the top. In the chart pane, you can slide up or down if it fills more than the screen.
To add your firearm, or firearms to the ballistics calculator, follow the above steps and add your firearm. You will need to find or measure the parameters needed. These parameters can most likely be found in your rifle and scopes manufacturers catalog or website. Sight Height can be measured as the distance from the center of the bore to the center of the scope tube. This measurement should be taken with care but is not all that critical. A number within 1/16th of an inch will serve our purposes. Until we prove otherwise, leave the Elevation and Windage Correction Facotrs as 1.0.
To add your ammunition, you can select your bullet from the bullet library if possible. Some newer projectiles are not listed, such as the 140 ELD-M we used above during the time of this writing. If you need to enter you projectile parameters manually, the bullet manufacturers list ballistic coefficients and usually the length. The length can be measured with calipers on a component bullet if that dimension can not be found. Be sure to match the Drag Model to the Ballistic Coefficient numbers found. Muzzle velocity should be measured with your ammunition and rifle using a chronograph in the weather you will be shooting in. If you are not able to get your muzzle velocity, an educated guess from the ammunition manufacturer or reloading manual will serve the purposes of experimenting with ballistics but will fail you in long range shooting.
website - http://www.shooterapp.net/Shooter
manual - http://www.shooterapp.net/manual.php
Applied Ballistics: Barometric Pressure vs. Station Pressure - http://appliedballisticsllc.com/ufaqs/barometric-pressure-vs-station-pressure/
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