triangulation bar
Today BB and his neighbor make triangulation bars.

This report covers:

  • Triangulation
  • Align two things
  • Training
  • Here — hold my beer!
  • How it works
  • Will it work at 5 meters?
  • Details
  • Summary

I have written several times about the triangulation method of teaching new shooters how to sight a target with peep sights. Today we will see how it works.

Triangulation

When we teach a new shooter how to use the sights on a target rifle there are many approaches that work. The most common way is to explain how the sights work and then let the shooter begin shooting. As they shoot they eventually understand the sights at a visceral level and begin to use them correctly. This is much like learning to ride a bicycle.

The thing is, when a target peep sight is used, people think it is somehow more complex. They think the shooter has to align the front sight with the rear sight peephole and also with the target. That may be how open sights work, but it’s not how peep sights work. I have found the triangulation method of teaching the use of peep sights to be most effective over the 55+ years I have been teaching. It’s the way I was taught when I was nine years old and it’s stuck with me all my life. In the 1990s I used it to teach a team of youth marksmen.

Align two things

With a peep sight you don’t need to be concerned with the rear sight. Simply look through the peephole and align the front sight with the target. Your eye automatically centers the image you see in the peephole, because that is where the most light is. It’s much faster and also more precise than traditional open sights, which is why armies around the world have been using peep sights for the past 150 years.


The Buffington rear sight was invented by Colonel Buffington at the Springfield Armory. It began to be deployed in 1884.

And, you can use a regular front sight post with a peep. It’s a little more difficult to use than a front aperture-type sight when you shoot at bullseyes, but it does work.

sight picture open sight
Remember that the shooter sees this through the peephole of the rear sight, which is what the large black circle represents.

sight picture aperture sight
And here is a sight picture with a front aperture. This is much easier to align with a bullseye.

Training

When I worked with a junior marksmanship team years ago, they did not want to make the triangulation bars I’m about to show, so they just laid target rifles on boxes that were cut out to hold them level. Then the students used the sights on the rifle in the triangulation exercise. This is harder to do because when the student looks through the rear sight they tend to touch and move the rifle, throwing the exercise off. When you see the exercise and especially when you do it, you will understand.

Here — hold my beer!

My neighbor, Denny, comes over in the afternoon on many days and we sit and talk about things. I was telling him about triangulation and how I needed to make two bars for my Royal Rangers marksmanship class that’s coming up in a couple weeks. I told him about the cards I expected to use as sights. Then I told him that Mac had given me some real peep sights and he said, “Let’s make the bars with those!” So we did. And when I say “we” I mean Denny made them. Anything that involves wood, other than a fire, gets passed to him.

triangulation sighting bar
This triangulation bar uses a post front sight. An aperture can be substituted, in the same way.

How it works

The bar is set up on a box and must not move. The instructor stands downrange and moves the target according to the shooter’s instructions. When it is perfectly centered in the front sight the shooter says to mark it and a pencil point is pushed through the center of the bullseye onto white paper behind the target, taped to a cardboard box. Obviously everything has to be aligned before any of this will work.

instructor moves target

After the instructor marks the target the first time he moves it away and the shooter talks him in a second time, then a third. When the exercise is finished there are three dots on the white paper. If they are close together the shooter will have aligned the target with the sights three times perfectly. If not, further training is needed.

pencil marks


Will it work at 5 meters?

I will be training kids to shoot with the Daisy 499B at 5 meters. When I last did this exercise in the 1950s the instructor marking the target was 50 feet away. And when we did it for the youth marksmanship team in the 1990s the target was 10 meters away. To help with the precision, Denny made the triangulation bar 30 inches long instead of the 18 inches shown in the drawing. That makes the sight picture more precise. I figured it would work, so I had Denny sight while I moved the target for him. Look at the results.

triangulation setup
This is the triangulation bar set up for the exercise. It took some shimming with boxes to get it to the same height as the target paper 5 meters away — plus to be comfortable for the shooter.

target
Three dots taken at 5 meters. This shooter is ready to shoot!

Details

Not many people are going to make these bars with $200 worth of vintage FWB target sights. The paper cards shown in the drawings above work just as well. Remember — you don’t move the sights or the bars. You move the target. Denny is just a perfectionist and I figured, as long as he was offering and I had the sights, why refuse? I now have two training aids that should serve me for years to come.

bars
Denny made me two excellent triangulation bars — and they work!

rear sight
The rear sight is held down by two screws. This is why we used the FWB rear sights.

front sight
The front sight clamps to a raised wooden “dovetail.” That raised piece is attached to the bar with a screw.

Summary

I did this project to get ready to teach the Royal Rangers to shoot. But I wasn’t sure I could do triangulation in the 16 feet 4 inches that 5 meters affords. Now I know for sure that it can be done in that short distance, so if you ever need to train someone to shoot with target sights — this is the way to do it.