Part 1: The introduction.
I did a lot of research and cannot find any information showing that other people use anything other than rear and front sight (two-point sight system) when shooting with iron sights.
I am not sure when I discovered the three-point sighting method but I guess, as it was after the posting of a review about my Cometa Indian pistol, that it should have been sometime in 2012. I had an accuracy problem with the Indian and it was reviewed in this post.
topic48992.htmlWhen I bought the Cometa Indian, I shoot it as a pistol because this is what it is. I could not hit where I was aiming so I made other sights. Even with the new sights I was not happy with the results, so I transformed the pistol into a short carbine with the addition of a shoulder stock and it slightly improved the situation. All became dependent on my cheek weld and it seemed that I was not 100% consistent so I continued to miss the target once in a while.
This was something I also noticed when shooting my air rifles. With an aperture sight at the rear and globe sight with a ring at the front I was scoring a lot better than when the rifle had a notched sight at the rear end of the barrel and a blade at the front end. After thinking about it, it made sense. The peep sight is close to the eye and the cheek weld has to be right in order to look through the hole so it probably helps with getting a consistent position.
I will go over a simplified explanation of the normal two-point sight system compared to the three-point sight system I am using. The examples will be with a rifle which has the notched rear sight at the rear end of the barrel (or about at the mid-point of the rifle) and a front post at the front. The eye must line up with both sight components and the target in the background to obtain the sight picture. If everything is perfectly lined up the projectile should hit the target where we are aiming. The problem is that it is impossible to hold still and the rifle will wobble sending the pellet somewhere into that probability zone. When the hold is not perfect or the sight picture is slightly off, it will create an angular error amplified by the wobble and the hitting zone will grow larger than if the cheek weld and sight picture are perfect. The three-point sight system adds a peep sight at the rearmost position on the rifle. This helps to get a repeatable cheek weld and also, because of the small hole in the aperture sight, to get the best focus possible on the front sight.
This is shown in a pictorial format below.
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To confirm what I was suspecting, I modified my carbine arrangement and added a tang peep sight to have an aiming reference closer to my eye. The result is shown in the pictures below.
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After the shooting improvement experienced with the Cometa Indian I started to modify some of my air rifles.
The next in line were both of my IZH 61 with two different homemade rear peep sights. The one in the top right picture was made from bent aluminum sheet metal and the one in the lower left picture started its life as a piece of an extruded aluminum window frame.
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I was on the right track and both rifles were shooting better than before.
R-Gun Pete