When I train at home I can never have the right distances to set my targets, so I end up shooting much shorter distances. This generates two problems:
- The angle of my arm is not right
- The size of the target is too big
So I decided to create and share a calculator to figure out what was the right height and size of the black depending on the distance.
But the target height does not change, it is an official measure!
Of course it does not, but relative height and size do. Even if the target is at a fixed height, as you move far from it the angle of sight changes and the target seems to go up. You want to keep your arm angle even if the target is at 2 meters instead of 10. Do a test, point at something with your hand and move back keeping your arm steady in the same position: you will see how the target goes up!
The size of the target also changes because what you care about is keeping the apparent size, so that the black looks to be the same size over your front sight. If you look at a dot in the wall or at your target and you start walking back, you will see how it becomes smaller and smaller.
And what about shot points?
I only do dry firing at home and shooting at the range. As soon as you change the distance scoring does not matter: the holes are bigger, the ballistics are not the same (specially at longer distances).
There’s a lot of dry firing work, get the best out of it.
I solved this using basic maths and the triangle calculations of the Pythagorean Theorem.
What I’ve done is create a right triangle with vertex (the corners of the triangle) at the height of the center of the target and also the center of my eye.
Knowing the distance at home from myself to the target I can calculate the size of the triangle and with it the height: to keep the same line of sight angle I have to raise the distance line.
How to use the target size and height calculator
So here is the calculator. To use it you just have to put on your shooting shoes and have someone measure the distance from the floor to the center of your eye while in shooting position. Then you can adapt the fields that have a yellowish background to your needs, starting by choosing an event from the list under Event.
I have included official heights and sizes of the black for different ISSF events to the right, the light blue cells. You can use them as reference or measure at your club (the height of the target in mine is at 141.5cm, well within the 5cm allowance of the ISSF for air pistol), but it may be good that you change it a bit regularly, as not all ranges setup the targets at exactly the same height. You want to be able to learn to get the right sensations even if there are changes.
There’s a Custom row to add any other discipline that you are interested in. If you send me the official distances and sizes I will try to add them to the calculator.
There is an unaccounted small distance also from the 10m mark to your eye, so this should have a small impact on the angle of your arm. I’ve not yet figured out how much to add. It may not be precise enough for a rocket, but it should be more than precise enough for me 🙂
To print the targets you have the total size in the bottom and also the relation to the original size (as a number, a fraction and a percentage). You can get some PDF targets here and use the printing dialog to scale it to the needed size. Check with a ruler afterwards that the size is good.