It is undeniable that modern optics have revolutionized the way people operate their rifles, providing an incredible degree of versatility and control. This enhancement allows for easier target acquisition and shooting at greater distances while improving sight picture at close range.
Among the popular optics, such as red dot sights and variable power optics, the prism scope is often overlooked despite being a high-performing optic. Prism scopes are incredible optics that provide a wide array of benefits to your rifle. Available in different magnifications, they are essentially a middle-ground between variable power optics and red dots.
Their durability and versatility make prism scopes suitable for various purposes like recreation, competition, duty, and hunting. In this article, we’ll be breaking down the advantages that prism scopes have and why you should consider using one on your next rifle build.
What is a Prism Scope?
To put it simply, a prism scope is a type of prismatic optic that utilizes etched reticles and fixed magnification. They are called prism scopes because they employ internal glass prisms to fold light within the optic, shortening the optical paths between the objective and ocular lenses.
While similar in practice, they differ quite substantially to some of the other common optic types available. For one, prism scopes don’t have any type of variable magnification. Instead, they utilize fixed magnification, usually ranging from 1x to 6x magnification, depending on the make and model.
Another key difference is the size of the overall optic. Optical prisms require a lot less space than the complex lens arrangements found on traditional rifle scopes. Because of this, they have a much smaller overall size and mounting footprint that’s more akin to what you would expect to see on a red dot sight. Do keep in mind that the size of the optic will increase with larger magnifications, but they are still considerably smaller than most scopes.
This guide offers an in-depth on the intricacies of prism optics and their internal functionality.
How does a Prism Scope Work?
Like we said before, prism scopes use solid glass prisms (as well as lenses) in order to magnify an image. Compared to other optics like red dot sights, they are quite different. Like rifle scopes, prism scopes have etched reticles, which are made by physically etching the glass of the optic in the shape of the reticle.
These reticle types are very durable and allow manufacturers to incorporate complex reticles with ballistic drop compensation and milling grids, whereas red dots tend to use either a single dot or a circle dot reticle. Optics like those in our SLx® MicroPrism™ series are available with different reticle patterns like the ACSS Raptor and ACSS Aurora MIL reticle, to name a few.
In contrast, red dot sights project the reticle onto the objective lens. In most red dot and reflex sights, the light is emitted from the rear portion of the optic and reflected back at the user by the front lens. Holographic sights do something similar to this, but instead of reflecting the beam once, the light is bounced off of several prisms/mirrors to create a hologram reticle that floats in center of the optic.
Prism scopes are often illuminated to be easier to see in both brighter and low light environments, giving the same bold contrast as a red dot. However, if your battery were to die when in use, you would still be able to see and utilize the reticle since it’s etched into the glass, which is just one of the many benefits you can expect when running a prism scope on your rifle.
Advantages of Using Prism Scopes
If you’re considering running a prism scope on your next rifle build, we’re sure you’ll be quite happy to learn that they provide a lot of benefits. These advantages tend to be relative, however. Compared to a red dot sight, a prism scope will almost always offer more in terms accuracy and overall precision. When compared to something like a low power variable optic though, prism scopes will be less precise due to the limited magnification, but they make up for it with reduced weight and a wider image.
Regardless, they still make for a great optic. Below, we’ve broken down some of the key benefits provided by this optic variant:
Enhanced Accuracy and Target Acquisition
We mentioned before that prism scopes can be a host to a vast array of different reticle patterns. As such, they offer enhanced levels of precision when compared to standard iron sights and red dot sights. The ability to run etched reticles with more complex patterns sets them apart from basic red dots while providing enthusiasts with a greater ability to acquire and accurately shoot targets.
Complex reticles offer more in terms of bullet drop compensation (BDC) and ranging stadia. Red dots can have complex reticle patterns, but they often leave something to be desired when shooting at longer distances. Variable power optics are great for distance, but they take more space on the rifle and tend to be heavier. Prism scopes essentially blend these two optic types together, giving you the best of both optics: the reticle of a traditional scope and the form factor and speed of a red dot sight.
Generally, prism scopes allow enthusiasts to acquire targets quicker than irons or rifle scopes. In fact, a 1x prism scope can even be as quick to pick up as a red dot sight. While higher magnifications can negatively affect speed, 2x and 3x options are in the sweet spot that allows you to shoot with both eyes open, allowing you to see more of your target and what’s beyond it.
Higher magnifications have their benefits, though. Their higher power allows you to get a better sight picture on targets at longer distances. Many enthusiasts will often opt for a higher power prism scope, usually anywhere from 3x to 6x magnification, for long distance shots while running an offset red dot sight for closer engagements. Ultimately, it’s up to personal preference, but the smaller overall size of prism scopes allows you to run multiple optics without adding too much extra weight to your rifle.
Size and Field of View (FOV)
Prism scopes provide great eye relief. While the unlimited eye relief on red dot sights is hard to beat, 1x prism scopes provide a similar, if not the same, degree of eye relief. For instance, the eye relief on our SLx 1x MicroPrism™ Scope is incredibly forgiving and can be used in tandem with a magnifier. While you can’t use a magnifier with magnified prism scopes, they offer a better FOV when compared to variable power optics at the same magnification.
Higher magnification scopes will have increasingly more restrictive eye boxes, making them less useful in scenarios that require fast target acquisition and overall speed. Though they can be slower to acquire a target, 4x, 5x, and 6x optics can provide a tighter target image. This makes higher magnification optics great for a variety of applications; they provide you with a more detailed target image, in a lighter overall package.
Durability and Reliability
While scopes and red dots are plenty durable, prism scopes are known for their exceptional reliability, even in some of the most demanding environments on earth. Optics like the Trijicon ACOG, for example, have been in use by military forces and select law enforcement units for decades, and they are renowned for their effectiveness in adverse conditions.
Similarly, our SLx MicroPrism™ series optics underwent strenuous and intense field-testing to ensure they could perform in harsh conditions. While other red dots, iron sights, and variable power optics can all be durable and reliable options, the compact size of prism optics paired with their reliability makes them worth considering for your next build.
Prism Scope Models and Brands
There are a lot of manufacturers that produce high-quality optics, each with their own reticle and magnification levels. Some popular options are the Primary Arms SLx MicroPrism™ series, the Vortex Spitfire series, and the Trijicon ACOG series.
Each of these optics is available with different magnification levels, reticles, and illumination types. SLx MicroPrism™ scopes and Vortex Optics Spitfire scopes are both illuminated using internal diodes, but the ACOG from Trijicon is a bit different. It uses dual illumination, wherein a fiber optic tube infused with tritium is used to illuminate the optic. In dark environments, the tritium ensures that the optic is still visible even though the fiber optic isn’t exposed to too much ambient light.
There’s a lot to go over when comparing these optics. Fortunately, our guide on the choosing the right prism scope magnification goes more in-depth on the differences of these optics while also breaking down the importance of choosing the right magnification for your intended purpose. We highly recommend checking out this article to round out your knowledge of prism scopes.
Wrapping it Up
Prism scopes are often overlooked by enthusiasts, but the benefits make them an incredible option to add to your rifle.
Though they aren’t without their drawbacks, they excel in a myriad of applications and can be incredibly versatile for recreation, hunting, competition, and personal defense. If you’re still on the fence about which optic you should choose, our guide on red dots vs. prism scopes breaks down the pros and cons of each of optic type in a head-to-head comparison.
Whether you’re looking at a Primary Arms prism scope or something like the Trijicon ACOG, you can rest assured knowing that a prism scope will greatly enhance your setup.
