How Do Rifle Scopes Work? The Science behind Your Optics!

Do you know what the basic functionality of a rifle scope is? In simple words it can be said the alignment of the barrel of a rifle with the target. Behind the scene, things are much complex. Let’s know what happens under the hood of a rifle scope.

In order to understand the mechanism of rifle scope, we will discuss both internal and external components of the scope and functionality. Let’s start.

There is a good similarity between the mechanism of rifle scope and telescope. Each scope has a an objective lens located in the front side of the scope. The function of objective lens is passing light into the scope. There is an ocular lens located at the rear end of the scope, which is also close to your eyes.

The function of ocular lens is to create an image of the target so that shooters can see it through the lens. Besides objective lens and ocular lens, there is other lens too. They also contribute to the functionality of scope. For example, behind the objective lens, you will find focus lens. This lens focus objects onto ocular lens.

Another object is erector tube. Erector tube is located between the objective lens and the focus lens. The erector tube houses the magnification lenses and the reticle. Often shooters term reticles as cross-hairs. Reticles are used to aim the rifle.

The magnification lens of variable scope is movable. There are two types of scope-variable and fixed. In variable scope, when magnification is lowered, the magnification lens moves closer towards ocular lens. For example, the magnification of a variable scope is 3-9x scope. It means the scope can enlarge a target 3 times to 9 times more than naked eye. So, if you lower the magnification power to 3, the magnification lens will be at the closest distance of ocular lens. If you increase the power to 9, the magnification lens will stay close to the objective lens.

The reticle is mounted either in front or rear of the magnifying glasses. Position of reticle determines the image size of target. When the reticle is mounted in front of the magnifying lens, the size of reticle will change with the change of magnification. On the other hand, if the reticle is mounted at rear end of the magnifying lens, the size of reticle will remain the same whether magnification is changed or not.  

The body of the scope is a metal tube. It holds the lenses in place inside the scope. Other necessary controls of the scope are located at the external part of the scope. Hunters used these controls to adjust the lens so that they can get a clear image of the target.

The font end of the scope is usually designed wider. It is designed in such way so that the front end can house objective lens. Similarly, the rear end of the scope also keeps wide to accommodate ocular lens.

At this point you may interest to know more about rifle scope? Here is greatarticle that have a good discussion on rifle scope.