We are kicking off a brand new series on our website: Lapua Ballistics app tips! Get the most out of our free of charge ballistics calculator by following our tips which we will be sharing all through year 2020.
Tips in the series:
NEW: The Sight-In POI feature
Coming up next: Coriolis effect, Benefits of 6 DOF calculation and Trajectory calculation for bullets and cartridges
EASY APP SETUP: If you haven’t tried our app yet, download it and check out our guide for easy setup!
TIP: The Sight-In POI feature – how to use several cartridges in the same firearm
Sight-In POI is a tool that can be utilized when you need to use several different types of cartridges in the same firearm without changing the basic sight-in setup of the scope. Knowledge of how different types of cartridges behave in your own rifle extends, for instance, the practice season well into the hunting season, and it means you can use the appropriate ammunition in any situation without having to sight-in the firearm again. When using the Sight-In POI feature, several different cartridge variations can be built around the sight-in settings of the rifle’s primary cartridge, depending on what cartridge needs you have.
How to use the Sight-In POI feature in Lapua Ballistics:
- Make sure you have set the reticle click units for your scope correctly in the app.
- Select the rifle profile you want to use as your primary profile and primary cartridge and sight-in the rifle to suit it.
- Copy the primary profile under another name (eg. Cartridge 2), select your preferred 2nd cartridge and set the correct muzzle velocity for it
- Test shoot the 2nd cartridge at your preferred distance without changing the scope settings.
- After test shooting, measure the distance (height and width) between the hits of the shot group and the point of aim, and calculate how many scope clicks this difference corresponds to.
- Alternatively, you can determine the corrections by re-sighting the rifle with the 2nd cartridge. When choosing this option we recommend zeroing the turrets for the primary profile. Next, carefully calculate the needed number of clicks for Cartridge 2. Once you have the number of clicks add them to the Sight-In POI Elevation and Windage windows of your Cartridge 2 profile.
- Enter a positive number if the 2nd cartridge hits above or to the right of the point of aim, and a negative number if it hits below or to the left.
- Similarly, you can also set the click corrections for your 3rd cartridge etc.
EXAMPLE: Sighting in a FMJ cartridge
You want to use the Lapua Naturalis cartridge with the N558 bullet as the primary profile and create a parallel profile in the same rifle using the 8g FMJ (S374) bullet. àCopy the Naturalis profile and start updating the copied profile with the FMJ cartridge data. When sighting-in, the FMJ cartridge shot group hits the target 4cm above the point of aim.
- Select Manage Rifle / Cartridge Data from the menu, activate the Sight-In POI feature, enter the value 4 in the Elevation POI Up column (in the example case, the sight-in distance is 100m and the scope click setting 1cm / 100m). Save the profile after changing the settings.
- In the Calculator view for a shooting distance of 100m, the needed correction indicated by the calculator should now be ↓ 4 clicks, and in the crosshair view, the point of impact for the shot group should be slightly above the center grid.
Good to know about the Sight–in poi feature