Semi-Automatic Rifle Scopes: Choosing The Right Optic For You

I often get asked which scope or optic is best suited towards a semi-automatic rifle or carbine, particularly when referring to the AR15, but there is no simple or straightforward answer to this question. So if you had to choose one optic for your semi-automatic rifle, what would it be?

The answer is largely dependent on how the rifle will be used, and what the shooter is hoping to achieve with that rifle. Budget, weight, durability, simplicity, and distance are all factors that should contribute towards making a well informed decision when selecting an optic. I can say however that the low power variable optic is rapidly gaining popularity and may be the preferred modern optic for many semi-auto rifle owners.

The following list gives a brief insight into which optics are best for which applications, and will be discussed in more detail later on.

  • Reflex Sights – close range & unconventional shooting styles
  • Holographic Sights – close range & unconventional shooting styles
  • Magnifier Optics – enhancing holographic sight capability to medium range
  • Prism Sights – close and medium range
  • Low Power Variable (LPV) Scopes – close, medium and long range
  • Variable High-Power Scopes – medium and long range

Note: the definition of long range is a topic of large debate, and is often determined by a rifle/ projectiles own specific capability. When referring to medium range throughout this article, we will refer to distances between roughly 200 and 350 meters. When referring to long range, this capability will extend outward beyond 500 and up to 800 meters, and possibly further.

Our pros and cons will be aimed towards mid & higher-end optics, with cheaper entry-level options possibly lacking some features in usability and robustness. 


Reflex Sights

This is what most people imagine when using the term “red dot sight”, whereby a red or green aiming point is projected forward onto a lens, which is then reflected back and onto the shooter’s eye. The reflex sight typically comes in two distinct looks, that being either an exposed HUD style (Heads-Up-Display) or a Tube-shaped optic. 

Reflex Sight PROS:

  • Very fast target acquisition
  • Unlimited eye relief & Parallax free (model dependant)
  • Shooting with both eyes open is easy (for situational awareness)
  • Intense reticle brightness even in bright sunlight
  • Unrivalled battery life
  • Extremely light weight
  • Low profile options available
  • Illuminated dot for shooting in low-light
  • Ability to Co-Witness with iron sights
  • Value for money

Reflex Sight CONS:

  • No battery means no sight picture, as there is no etched reticle
  • Dot sizes can become large (up to 6MOA) and obscure targets down range
  • No magnification to aid accuracy or target identification
  • Advanced reticle features are not present for shooting at longer distances
  • Eyes with astigmatism (blurred vision) may struggle with the dot’s appearance

Approximate weight: 29 grams (HUD style) or 200 grams (Tube Style)

Approximate Price: $200 – $400 or R4 500 – R8 000

If close range engagements and shooting from unorthodox firings positions are your thing, with little or no requirement to shoot targets at distances, and you are limited in terms of budget, then a reflex sight might be the best choice for you. 


Holographic Sights

The holographic site is optically, electronically, and otherwise superior to reflex sights, but comes at a much higher price. EOTech is the leading manufacturer of holographic sites with various options available. Vortex Optics currently has its own version which is gaining popularity. The optic uses laser-driven holographic technology, allowing the shooter who is looking through the sight window to see the reticle image in the distance, at the target plane. The result is a far more precise and clearer target reticle which is far more forgiving to errors in head placement and eye relief, which in turn allows for faster target acquisition. 

Holographic Sight PROS:

  • Extremely fast target acquisition
  • Unlimited eye relief & Parallax free (model dependant)
  • Shooting with both eyes open is easy (for situational awareness)
  • Intense reticle brightness even in bright sunlight
  • Smallest and most precise dot size (1MOA) with a larger outer ring for fast target acquisition
  • Excellent battery life
  • Light weight
  • Illuminated reticle for shooting in low-light
  • Ability to Co-Witness with iron sights
  • Can be used with night vision (and NVG intensifier tubes, with no halo effect)
  • Projected reticle is visible to only the operator (no muzzle-side signature)
  • Less distortion towards eyes with astigmatism (compared to reflex sights)

Holographic Sight CONS:

  • No battery means no sight picture, as there is no etched reticle
  • No magnification to aid accuracy or target identification
  • Advanced reticle features are not present for shooting at longer distances
  • Expensive

Approximate weight: 350 grams

Approximate Price: $600 or R13 000

If extremely accurate close range engagements and firing from unorthodox shooting positions are your thing, and you wish to purchase a top-of-the-range optic without any budgetary constraints, or if you wish to purchase an optic that works best in conjunction with a magnifier, then a holographic sight might be the best choice for you. 


Magnifiers

The reflex and holographic sight’s simplicity and lack of magnification are their biggest strengths in fast target acquisition and close quarters shooting, but beyond 100 meters, these strengths can become their greatest weakness. This issue can in many cases be resolved by adding a quality magnifier, which most commonly comes with a fixed 3x zoom and has the ability to flip-down when not is use. 

Common Misconception: many believe that a red dot reticle will grow proportionally to the added magnification, therefore increasing the dots MOA and drastically reducing accuracy potential. This is incorrect. While the dot size will grow (commonly by 3x), so will the target. As a result, the dot size will remain the same in relation to the target.

Magnifier PROS:

  • Adds magnification for enhanced accuracy and target identification 
  • Does not affect rapid target acquisition when flipped out of the way

Magnifier CONS:

  • Limits field of view and requires correct eye relief & parallax
  • Can only add one magnification level 
  • No compensation for bullet drop
  • Adds weight and bulk to the rifle

Approximate weight: 300 grams (approximately 600 grams with primary optic)

Approximate Price: $350 or R6 000 (excludes reflex / holographic sight)

Ideal for increasing magnification for enhanced accuracy and target identification when placed behind a reflex or holographic sight.


Prism Sights

A prism sight is a short, tube-style optic that uses a prism to focus the image that is seen when looking through the scope. They are much smaller and lighter than traditional rifle scopes, and come with a fixed magnification, typically a 3x or 4x with an etched reticle. The Trijicon ACOG is a very well known prism scope that is used as the standard issue “battle optic” on many military assault rifles. The Vortex 3x Prism scope is also growing in popularity, and will prove to be a good choice for someone who wants an affordable scope that can do it all. You could almost think of the prism scope as a jack of all trades, but master of none. However, invest the right amount of training into your prism optic, and its true potential may surprise you. 

Prism Scope PROS:

  • Fast target acquisition
  • Illuminated reticle for shooting in low-light
  • Etched reticle which keeps optic running during battery failure
  • Small and crisp reticle for increased accuracy (with larger outer ring for fast target acquisition)
  • Magnification for enhanced accuracy and target identification at further distances
  • Advanced reticle features (bullet drop compensation)
  • A good choice for eyes with astigmatism

Prism Scope CONS:

  • Limits field of view and requires correct eye relief
  • Eye relief is shorter than LPV optics and conventional rifle scopes
  • Slower target acquisition than reflex sights, holographic sights and LPVs
  • Only one magnification level, limiting accuracy and target identification at long ranges

Approximate weight: 450 grams

Approximate Price: $500 – $1200 or R8 500 – R30 000

If extremely accurate close to medium range engagements are your thing, while retaining a lightweight weapon system that has the ability to operate without batteries, then a magnified prism sight might be the best choice for you.


Low Power Variable (LPV) Optics

The LPVO is a low power rifle scope which is rapidly gaining popularity amongst owners of AR style rifles, and can be found on many designated marksman rifles (DMRs) which require both close and long range capability, and are able to accurately shoot targets beyond 500 meters. The optic allows for fast target acquisition at closer distances, with the ability to crank up the zoom and use advanced reticle features to compensate for bullet drop and wind drift when engaging targets at longer distances. Higher end manufacturers offer extremely durable LPVOs with illuminated daylight red-dot reticles which add tremendous value to the optics close range success.  

LPVO PROS:

  • Very Fast target acquisition at 1x zoom
  • Shooting with both eyes open is easy (at 1x zoom, for situational awareness)
  • Illuminated reticle (or red dot) for shooting in low-light
  • Etched reticle which keeps optic running during battery failure
  • Small and crisp reticle for increased accuracy
  • Magnification up to 6x or 8x for enhanced accuracy and target identification at further distances
  • Advanced reticle features (bullet drop compensation and range estimation) for shooting at longer distances

LPVO CONS:

  • Adds weight and bulk to the rifle
  • Limits field of view and requires correct eye relief
  • Slower than a red dot when shooting from unorthodox positions
  • Expensive (and requires a scope mount)

Approximate weight: 850 grams (including mount)

Approximate Price: $400 – $900 or R8 000 – R16 000 (excludes mount)

If extremely accurate close to long range engagements are your thing, without any budgetary or weight constraints, or if you are building a DMR, then a low power variable optic might be the best choice for you.


Variable High Power Optics

There are many variable high power scopes that come with modern tactical features and advanced reticles, proving to be of great value on larger caliber semi-automatic rifles and DMRs that require long range capability. While they may fall short when it comes to close range engagements, users often attach light-weight HUD-style reflex sights, typically offset at a 45-degree angle, which assists the rifle in covering the full spectrum of close, medium and long range capabilities. The complete setup won’t come cheap, and will add a considerable amount of weight to any rifle, but may be the perfect combination to fill specific roles, particularly when long range stopping power is essential.

Variable High Power Scope PROS:

  • Ideal for larger caliber rifles 
  • Illuminated reticle for shooting in low-light
  • Etched reticle which keeps optic running during battery failure
  • Advanced reticle features (bullet drop compensation and range estimation) for shooting at longer distances
  • FFP (first focal plane) options for advanced shooting techniques at longer distances
  • High magnification for enhanced accuracy and target identification at long distances

Variable High Power Scope CONS:

  • Slowest close range target acquisition (unless a reflex sight is fitted)
  • Heavy and Bulky
  • Limits field of view and requires correct eye relief
  • Expensive (and requires a scope mount)

Approximate weight: 925 grams (including mount)

Approximate Price: $1200 or 18 000 (excludes mount)

If extremely accurate medium to long range engagements are your thing, without any budgetary or weight constraints, or if you are building a DMR chambered in a larger caliber, then a variable high power scope might be the best choice for you. Consider adding an off-set reflex sight for those rapid close range shots. 


Conclusion

While there are hundreds, if not thousands of optics to chose from, all housing their own unique features and capabilities, you should now at least have a better understanding as to which optics fall under which category, and how their advantages may best suit your requirements. When it comes to purchasing an optic, having the correct knowledge and experience can really help in reducing the vast number of optics on the market to only a few good choices.

If you have any questions or would like any advice, get in touch or leave a comment below, and we’d be happy to help.

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