If you have shopped for around for an optical sight for your tactical rifle lately, you may have noticed a new term being thrown around that you might not be familiar with - the prism scope. A prism scope (sometimes also referred to as a prismatic scope) is a scope that uses a glass prism to focus an image as opposed to traditional rifle scopes which use a series of lenses. This allows for a more compact design while still allowing for many of the same benefits such as a magnified image, an etched reticle, reticle illumination, and a focusing eyepiece.
Prism scopes are typically available in lower range magnifications from 1x to 5x.
The compact size and lower magnification range makes them well suited for AR-15’s and similar tactical rifles. They serve as an attractive alternative to other short range optics such as ACOG’s, Aimpoints, or red dot sights.
Some of the key advantages of a prism scope over a red dot sight:
- A prism scope allows for magnification giving you a larger sight picture and extending your effective range.
- A prism scope allows for both an illuminated reticle system and an etched reticle. The etched reticle can be viewed without batteries or a fiber optic. This provides an extra layer should your illumination system ever fail you.
- A prism scope can utilize more sophisticated reticles that include ranging or bullet drop information.
- A prism scope uses a focusing eyepiece which allows you to adjust for personal differences in vision. This makes it a good option for people with astigmatism or other eyesight conditions who have difficulty using red dot sights.
Some of the drawbacks of a prism scope versus a red dot sight:
- A prism scope has a shorter, narrower eye relief that a red dot sight. This might make it inappropriate for shooters or firearms that require an extra long eye relief of 5+ inches.
- A prism scope with magnification has parallax just as a magnified rifle scope would. Optics with magnification are typically parallax free at a certain fixed distance (commonly 100 yards) with parallax coming into play at further distances. Note that the amount of parallax is negligible to most shooters and can be minimized with proper and consistent shooting position and cheek weld.
Given its attractive size, functionality, feature set, and increasingly attractive price point the prism scope is becoming a popular option for AR-15 owners looking for a middle ground between a rifle scope and a red dot sight.