August 28, 2015

FAQ – Frequently Asked Questions

Why do I need to create a Gun Profile

The Gun Profile contains essential information used to compute trajectory and bullet stability. This includes:

  • Sight height above the bore – Distance between the center of the bore to the center of the scope or the bead on the front iron sight. This is needed to compute trajectory.
  • Gun Sight zero distance – Distance at which the firearm’s sights are zeroed. This is needed for trajectory.
  • Rifling twist rate – The length in which the bullet make 1 complete revolution in the firearm’s barrel. This is needed for the bullet stability calculation.
  • Gun Weight – The weight of the firearm plus the scope if so equipped. It is needed to compute recoil force.

Once a Gun Profile is created it, it is associated (paired) with cartridges, which contain the bullet and charge information.

No Gun Profile is required when comparing cartridges. All cartridges compared use the same sight height and zero-in range. To see the trajectory of a cartridge not associated with a Gun Profile, select Compare Cartridges in the Main menu, select the cartridge of interest, select Done Selecting Cartridges in the options menu, and then select either the Show Table or Show Plot button in the Compare Cartridges activity.

Where can I find the information needed when creating a New Cartridge?

If you are using commercial ammunition, you may first want to see if it is already included in the Federal, Remington, or Winchester data included with the app. Go to Database Utilities, and select Import Guns Cartridges. Select the input file from the provided list, and hit “Select Specific Items” to search for the cartridge you are using.

If you are a hand-loader, you will know to consult the bullet manufacturer’s reloading manual or website to obtain the information required. Here is some additional information that will help:

  • Bullet Diameter – As expected this is the actual bullet diameter in fractions of an inch or mm. It is not always the same as caliber, since manufactures often name a cartridge to differentiate it from similar ones on the market. For example the 325 WSM actually uses a 8mm bullet which has a diameter of 0.323 inches.
  • Muzzle Velocity – Most manufactures of commercial ammunition state muzzle velocity on the box. Be aware that velocities are measured in test barrels that may be 24 to 26 inches long. If the test barrel is longer that the one on your rifle, it will increase muzzle velocity by about 50 ft/sec for every inch longer that it is. This applies to published hand-load muzzle velocities as well. The best source of muzzle velocity is from a chronograph measurement from your ammo and your gun.
  • G1 Ballistic Coefficient – provided by bullet manufacturer or ammunition manufacturer. It can also be computed if you know the bullet drop at two distances. Use the Ballistic Coefficient from Velocity utility found in Shooting Utilities on the Main Menu.
  • Bullet Length – Is used in the Bullet Stability computation. If you don’t want to check it, leave the value at zero. Otherwise, check the following websites:
  • Powder Weight – Is used in the Compute Felt Recoil computation. If you don’t wish to compute it, leave the value at zero. Otherwise, you can estimate its value here. Hand-loader’s already know what it is for their ammo.

Where is the Options (menu) button on my Android Device?

The options (menu) button is used to access context sensitive help information in the App.

The options button location depends on the device. It is always best to refer to the manufacturer’s documentation, but here are a couple hints:

  • Look for 3 vertical bullets on the screen of tablets or phones with no physical menu button.

  • On a phone look for a button with two or three horizontal lines, four small boxes, or a box within a box.

Why does the Keyboard cover the screen when it comes up?

The amount of screen real-estate covered depends on your Android device. On small phones, it can be the entire screen, on tablets in can be the bottom half. Try these techniques to get back your perspective:

  • On phones – complete your entry and hit the phones back button (not the delete button). It will hide the keyboard and leave your entry intact.

  • On tablets – the top half of the screen (not covered by the keyboard) is still scrollable, grab and drag to see any portion of the covered app.

  • Look for a down-carat character in the bottom tray. It will retract the keyboard, and you will be able to see the app again.

Why can’t I enter negative numbers in the Adjust Open Sight Utility?

You can, but it may be confusing – depending on your android device. Some devices combine the “-” and “.” characters on a single key (“-.”). If that is the case, watch the cursor prompt closely while hitting the “-.” key on the keypad repeatedly. The prompt changes from “-” to “.” and back again each time you hit the key. If you want to enter a negative fraction, do the following:

  • toggle the “-.” key until the cursor displays “-” then wait until the “_” disappears underneath it. The keypad is now ready for the next character input.

  • Toggle the “-.” key until the cursor displays “.” then wait until the “_” disappears underneath it. The keypad is now ready for the next character input.

  • Now enter the numerical characters.

Why does the App only run in Landscape mode?

So the reports don’t wrap on phones or small tablets. This makes them unreadable. Reports can be displayed in Brief, Normal, and Verbose layouts. Small phones will need to use the Brief layout. Android Best Practices suggests supporting screen rotation, but it is not a requirement. Until PDF reports are supported, this app will continue to run in Landscape mode.

Does the app compensate for the Coriolis Effect or Bullet Spin?

1-Shot does not currently compute a correction for either the Coriolis effect (earth rotation) or bullet spin. It was initially developed for use in medium range shooting (Hunting or Metallic Silhouettes), where targets are not normally engaged beyond 500 Meters. As you are most likely aware, the app would need to know latitude, and True Bearing to make the computation. It is currently only prompting for target relative bearing in the Target Solution computations.

Why don’t I see the sight picture after I enter the Running Boar Simulation a second time?

Depends on the state you last left it in. Hit the Align Sights button again to see them.