Low Power Variables vs Low Power Fixed Magnification

With my recent purchase of the newest generation of ACOG, and my ignoring the similarly priced low-power variable market, I thought it would be worth posting some of my thoughts on the two competing segments.

Browsing optics discussions on various gun boards would have you think that the age of the low power fixed magnification optic are gone. As one SME in the shooting world put it, “The ACOG was the perfect optic for pre 2004 conflict.” Even in my own article about different types of optics, I opined that low power fixed magnification (which I dubbed Class II optics) represented the skill set of the last generation of riflemen, before our focus turned to more close quartered combat.

Low power variable (LPV) optics have dominated the market in recent years. What started as a new concept useful for competitive shooters slowly worked its way into military units with the leeway to purchase whatever they wanted. Usage by these military units caused the civilian market to take notice. This started cycle whereby many companies entered the market and began innovating and driving prices down through competition.

The downside of the LPV has always been a combination of cost, weight, and durability. The added mechanisms required to change magnification meant introducing complexity and weak points. Combat-grade optics designed to survive harsh conditions necessitated extensive engineering, which increased cost. Up until very recently, you were unlikely to find a combat-worthy LPV for less than $2K. Competition in the market has brought that price closer to $1K, though, which directly competes with the ACOG segment.

With that in mind, why would anyone choose to go with a low power fixed magnification optic when it is possible to get a scope of comparable durability and optical quality for about the same amount of money?

Understanding Intangibles


For the sake of this discussion, I’m ignoring the market segment below $800. For now, I am purely talking about comparing optics like the ACOG and SpecterOS 4x to LPV scopes like the Vortex Razor and Nightforce 1-4x. Below $800, there are a lot of great LPV options from SWFA, Trijicon (the TR-24 has come down in price quite a bit), Leupold, and others. In that price bracket, there isn’t really much a difference between the fixed magnification and variable magnification scopes.

Once we cross into the realm of “enthusiast,” “prosumer,” or “professional” optics, things get more interesting.

We can list out all the specs on the various optics in these categories, examining weights, fields of view, illumination, reticles, parallax adjustment (or lack thereof), and other tangible items. The truth is that those things simply don’t matter as much in this bracket. In this segment it has much more to do with personal preference.

In the category of low power fixed magnification, optics tend to be lighter, brighter, more compact, and simpler in use. Most of the ACOG line, even the tiny TA-33 that weighs a scant 7 oz, have objective lenses wider than the average LPV (24 mm). That makes a difference in low light conditions, especially when it comes to target identification. Small sizes reduce snag hazards and overall bulk.

LPV scopes tend to be slightly more versatile for the roles they can be used in, and they often have more refined reticles, but come at the expense of increased weight and size. In general, I find the illumination to be weaker and more short lived due to smaller batteries. But that is with a sample size of three. I know there are some LPV options out there that are exceptionally bright, especially if they are fiber optic powered. LPV scopes might be friendlier to those with poor eyes, as things like parallax and ocular lens focus can be adjusted.

These are not absolutes, as there are some overlapping features depending on models in question, but this is a pretty good guideline to understand.


So who should choose what?

Having spent a lot of time with both LPV and fixed magnification, I can’t really see myself doing without either. Were I to be stuck with one rifle and scope for every task for the rest of my days, I would probably tend towards the variable market. But, since I’m not, I like having the option of taking a lighter and more compact scope with wide field of vision for some tasks. I like the simplicity of shouldering the rifle and firing, without worrying about fiddling with magnification settings or turrets that might have been bumped off of my zero.

In general, I would say the difference between users is this:

  • If you want magnification, but tend to stick to the 1x end of things (either via RDS or leaving a LPV at 1x), then stick to a LPV. I would avoid an RDS with magnifier arrangement.
  • If you tend to want magnification all the time, or have an LPV you leave on the high setting most of the time, and prefer the simplicity of shoulder-and-fire function while keeping a more compact package, consider a fixed magnification scope. You can always pair it with a mini RDS if you want to have that multi-role capability with minimal additional weight.
  • If you want magnification most of the time, precision is a priority, and you intend on fiddling with windage and elevation a lot, go with an LPV designed to do it. These will tend to have better reticles (MRAD/MOA) and matched turrets.
  • If you don’t know where you fall on this continuum, then it doesn’t really matter what you pick. In this case, I would consider getting a more inexpensive LPV and see how you tend to use it. As I said before, the sub $800 bracket has a lot of great options to start with and allow you to explore your preferences.

When I started this journey a few years ago, I was sure that I knew exactly what I wanted. I did my homework on internet, and I purchased quality optics. Ironically, one of those scopes doesn’t get used anymore and the other has been relegated to more of a backup role. The more experience I gain, the more I prefer the simplicity of grab-and-go without knobs and such to fiddle with. For that reason, I’ve been sitting strongly in the camp of fixed magnification scopes.



New Steiner Intelligent Combat Sight

The Firearm Blog recently broke a story about Steiner’s entry into the intelligent optics market. The Intelligent combat Sight (ICS) appears to be a pretty solid entry into Category V optics that I wrote about last year. Here is a quick video about the scope.


Interestingly, the optic housing looks suspiciously like something made by ELCAN, even though the companies are unrelated. It even has similar external adjustment mechanisms and backup sight configurations. While ELCAN is owned by Raytheon, Steiner is owned by Beretta. Of note, Beretta also owns Burris Optics, which is known for their Eliminator series that seems to have similar functionality to Steiner’s ICS. With a weight 27 ounces, it’s no lightweight- and the ranging mechanism on the left side certainly adds some bulk.

At $3500+, it is certainly outside of my price range, but still a fraction of what the TrackingPoint M600 system costs at nearly $10K (including the AR-15 pattern rifle). To me, this signals that the steady march of technology continues to bring prices down and improve ruggedness across the market.

Steiner has recently made splashes with the release of its M332 and M536 combat sights, which seem to offer great glass and ruggedness for half the price of an ACOG. If the trend continues, I really do wish them (and others) luck with bringing more options to bear.


New ACOG on the Market

It seems that Trijicon quietly released their newest addition to the ACOG lineup. The TA-110 builds upon the technology used in the TA02, which was essentially a battery powered TA01/TA31.


The TA-110 is effectively a battery powered LED TA-11. Why is this interesting, you ask? I always felt that the TA02’s success was hindered because the usefulness of its battery power was irrelevant next to the eye relief drawbacks of TA-01/31 series. The TA-11, on the other hand, negates most of those issues and was among the most popular competition optics on the market because of its balance of field of view, magnification, and eye relief.

Had the TA-110 been on the market last year, I very well may have purchased it over my ELCAN SpecterOS 4x. As it stands now, the ELCAN still fills my battery-powered fixed magnification combat optic niche, and I don’t see that changing any time soon. However, I still plan on picking up a fiber-optic powered TA11 to fill the no-battery role.

Something else to keep in mind is that the expansion of Trijicon’s battery powered ACOG line to the TA-11 means that a version of extremely popular TA33 might be just around the corner.

The addition of battery power increases the weight of the TA-11 from 14 oz to 16.8 oz without mount. That’s not light by any means- but it’s not a terrible increase, either. Whether the weight penalty is worth it to you depends on your uses.


Thoughts on Optics Selection

Like barrels, triggers, and any number of “choices”  on an AR-15, there are a lot of options out there for optics. There is also a lot of misunderstanding. I want to take a moment and discuss some thoughts on optics selection. There are already some really great guides out there, but they focus more on particular classes of optics. I will link to them as appropriate since I don’t feel the need to reinvent their excellent work. Rather, I want to look at a broader picture of why you might choose one class of optics over another, and how you might best employ them.

As a refresher, I have two fundamental rules for buying any firearms-related gear.

  • Let the mission dictate the configuration
  • Buy once, cry once

Now, let’s get to it.

The Everyday Marksman’s Five Classes of Optics

Zak Smith wrote a very detailed article for Shotgun News back in February of 2008 detailing his thoughts on fighting optics. In short, he categorized optics into three basic types: CQB, DMR, and SPR. Each type is best suited for different engagement ranges and weapon employment method. However, much has changed in the world of rifle optics since that article was written in 2008.

I break optics into five general classes:

  • Class I: Iron Sight Replacements
  • Class II: Low Powered Fixed Magnification
  • Class III: Low Power Variable Magnification
  • Class IV: Mid to High Magnification
  • Class V: Digital Hybrid

I derived these categories by using Zak Smith’s typography as well as the US Army’s
phased plan of optics evolution (previously mentioned as part of an Army conference back in June). Most shooters are reasonably familiar with the first four categories; the fifth may be news- but it is the future.

Screen Shot 2015-06-20 at 12.30.51 PMLet’s break down each of these classes.

Class I: Iron Sight Replacements / CQB


This class of optic is probably the most popular on the market, typified by the Red Dot Sight (RDS). Characteristics of Class I optics include zero magnification, parallax-resistance (not necessarily parallax-free), and a focus on speedy sight acquisition. This class of optic simplifies the sight picture by removing the need to align the front and rear sights with the shooter’s eyeball. The shooter keeps both eyes open and focuses on the target; the ‘dot’ is projected onto that same plane. From there, the task is simply to put the “dot” on the desired point of impact and squeeze the trigger.

I think of Class I optics as better versions of the M16A1 iron sights. You set your zero for a specific distance, usually a desired point blank zero, and then go fight. Use holdovers as necessary for anything outside of that point blank zero range. This class of optic excels from bad breath distance out to 250ish meters. They are lightweight, compact, and some can be left on for years before the battery needs to be changed. Some models do not have batteries at all, and will use fiber optics and tritium for illumination.

This class of optic rose to prominence during the conflict in Iraq and the intense CQB/urban operations it entailed. These optics are fantastic for use against moving targets or any situation where the speedy acquisition of a sight picture is the top priority. If you regularly shoot from unconventional positions where a proper cheek weld is difficult or unlikely, then these optics are king of the hill.


Class I optics are the only ones capable of co-witnessing with iron sights. That means that a shooter can attain a proper sight picture through the rear sight aperture and look through the optic to the front sight, and have all four elements (front sight, aiming point of the optic, rear sight, and the eyeball) all align simultaneously. This is valuable if the optic ever fails- the shooter can still use the iron sights without issue while leaving the optic in place.

While Class I optics are a great choice for a general use defensive weapon, they do have limitations. Shooters with uncorrected astigmatism may see imprecise blobs or clusters rather than nice crisp red dots (I find this is worse on battery powered options). The lack of magnification means that this type of optic is not ideal for observation tasks, and will be of little help for differentiating among targets or identifying a target in relation to its background. Furthermore, Class I optics are not designed to have their zero easily adjusted to account for various distance or windage scenarios. It’s all Kentucky Windage, all the time.

The New Rifleman has a very nice guide to Red Dot Optics and their use, so definitely check it out for more specific information.

My preferred Class I optics are Aimpoints (M3, M4, PRO, CRO, and T2), EOTechs (XPS series), and the Trijicon MRO (Note: With the recent revelations about EOTech’s performance issues in certain temperature ranges, I’m a bit more hesitant to recommend it for any purpose). There are other options out there at varying price points, but that is where the second law comes into play. If you plan on trusting your life to an optic, do not go cheap. The ones listed above are all extremely tough, and will handle more abuse than most people will probably ever throw at their rifles.

Class II: Low Powered Fixed Magnification


This class of optic is best typified by the ACOG. There are many others on the market, such as my ELCAN SpecterOS (pictured), the Leupold HAMR, IOR Valdada QR-TS, and the Zeiss ZO 4x30i. This class of optic  gained traction during the US Army’s Advanced Combat Rifle trials in the 1980s. Notably, Trijicon teamed with AAI to submit an early version of the TA01 ACOG on their rifle entry and ELCAN presented an early version of the C79 with Colt’s submission. While the replacement rifle never came to fruition, the optics did. Class II optics have grown more popular over the years as militaries have recognized the value of ruggedized magnified optics for general military use. They are typically compact, relatively lightweight, rugged enough to put up with the abuse infantry life, and offer huge marksmanship benefits over iron sights.

I would venture to say that Class II optics embody the skill set of the last generation of riflemen, before the focus turned to vehicle-borne operations and CQB. Class II optics truly reward proper execution of marksmanship skills, and they excel at the medium ranges that militaries have historically operated in (think 50 to 500 meters). The use of this type of optic assumes that the shooter will have time to see a target, move to appropriate cover, identify the target as a threat, and then apply marksmanship fundamentals to eliminate the threat.


The reticles in these optics usually have some form of rangefinding stadia and a calibrated bullet drop compensator (BDC). These are intended as field-expedient methods of estimating where hits will land and not intended for true precision shooting. The BDC reticles are usually calibrated to a specific bullet moving at a specific velocity under specific environmental conditions. Deviating from these standards means that the BDC will not be correct, but should still be “close enough.” This type of optic lends itself very well to Sniping 4th Generation (S4G) style shooting.

Class II optics are limited by the characteristics inherent in the bending of light to create magnification. That means that the shooter must have a consistent cheek weld to account for eye relief, parallax, and the exit pupil of the optic. Incorrect alignment results in poor sight pictures and missed shots. Relative to Class I optics, magnified optics are slower to move from target to target since the eye has to readjust and refocus as targets come into view. Class II optics, like Class I, do not usually allow for easy zero adjustment in the field for “dialing” shots. They are meant to be zeroed and left alone. Again, it’s all holdovers, all the time. Lastly, Class II optics are typically fixed at a certain parallax setting and do not have diopter adjustments to account for different people’s eyes.

A “horseshoe” fiber optic powered reticle on an ACOG
The “daylight” turned up to maximum power on my ELCAN SpecterOS
The “low light” setting, illuminating the entire reticle

Some of the more modern Class II designs indlue methods of illuminating the reticle. This works both for illuminating the aiming point at night, but also helps speed up shooting during the day. Brightly illuminating the center of the reticle helps “draw the eye” and give it something to focus on. This is the same concept as the old Armson Occluded Eye Gunsight (OEG), a 1970’s era South African precursor to Class I optics (Trijicon actually got its start as the importer for Armson). If the shooter keeps both eyes open and allows the brain to superimpose the illuminated reticle in front of one eye over the wide field of view of the other, it can be almost as fast as a Class I optics. Note that using magnified optics in this fashion can be affected by phoria, the intensity of which varies from person to person depending on eye dominance and other factors. Phoria is how far the alignment is off between each eye when focusing on a target. When I shoot using this OEG method, I know I will actually be aiming about 4-6 MOA to the right of the target when I switch focus back to my right eye.

Class II optics are best suited for practical marksmanship and general dismounted shooting, where a balance must be struck between speed and accuracy at a variety of distances (known and unknown).

My personal picks for Class II optics include the aforementioned Trijicon ACOG line (particularly the TA-11, TA-31, TA-33, and TA-44), ELCAN SpecterOS 4x, and Leupold HAMR. Note that all of these are fairly expensive, nearly double the cost of a quality Class I optic. Remember, you’re not just paying for magnification here, you’re paying for the durability.

Class III Optics: Low Power Variable


This class is fairly new and was developed to bridge Class I and Class II optics for competition. They will usually have some way to switch between 1x (“No” magnification) and some number greater than 1 (usually 4x or 6x). The traditional method is by moving the optics internal lenses via an exterior mechanical knob. That method allows the shooter to choose a magnification anywhere between 1x and whatever the top end might be. Another method uses a rotating prism and cam system that switches only between 1x and the top end, with no options in between.

I said “No” magnification because even though the image appears to not be magnified, the light is still passing through lenses and being bent. That means that you will still have to deal with the limitations that come with bending light, particularly eye relief, exit pupil, and parallax.

View through a Trijicon TR24G 1-4x scope set on 1x magnification. As long as the head is positioned correctly, this is almost as fast as a red dot sight

Class III optics will have a variety of reticle patterns and illumination methods. Some will have similar BDCs to Class II optics; others will have the MRAD and MOA reticles of Class IV optics. Some will illuminate the entire reticle, others will only illuminate certain segments that best draw the eye in CQB situations. The turrets on Class III optics may or may not be easily adjustable, it really depends on the design of the scope and where it errs more towards speed or precision. These optics usually have a diopter adjustment for eyes, and may or may not have a parallax knob (AKA a focus knob).


Class III optics offer a fantastic range of capabilities. Set at 1x, they are nearly as fast and user-friendly as Class I optics. Set at higher magnifications, they retain much of the same capability as Class II optics. I used to shoot several local 3-Gun matches with my trusty Trijicon TR-24G. Being able to use the big glowing green triangle up close at 1x and then quickly switching to 4x for 200-300 yard shots gave me a huge advantage. To an outside observer, they really offer the best of both worlds. But there are tradeoffs.

Class III optics are heavier than either Class I or Class II optics, usually weighing between 1 and 2 lbs without a mount. They also have increased mechanical complexity, which means there is higher risk of parts breakage. Overcoming the durability issue means increased cost in engineering, manufacturing, and parts. Trijicon’s VCOG, a Class III optic designed to be as tough as their ACOG line, costs around $2500. The ELCAN SpecterDR, which switches between 1x and 4x, is around $2200. If you don’t mind losing the ruggedness aspect of the high end options, other quality Class III optics cost between $600 and $1500.

Class III optics occupy a solid middle ground where they are the jack of all trades, but master of none. They are can be nearly as fast as Class I optics up close, but lose out due to eye relief and parallax. They can be as useful at distance as Class II optics, but are heavier and less durable. If you do not need to operate on the extremes of speed and/or durability, then the Class III is probably a good option for you.

If this is the way you want to go, I highly suggest The New Rifleman’s guide to variable optics.

As for myself, I wouldn’t spend less than $600 in this category. There are a lot of options out there, so do your homework.

Class IV Optics: Mid to High Magnification


This is the same as Zak Smith’s Type III optic for SPRs. I look at this category as optics geared more towards precision than anything else.

For the most part, Class IV optics have all the same traits as Class III optics, with a few notable changes. The low end magnification in this class is greater than 1x, and will usually be 2.5, 3, or 4x. The high end will probably be somewhere between 9x and 16x, or beyond. The reticles will almost always be of MRAD or MOA design, and turrets should be readily adjustable to account for range and windage. These are designed to effectively take the rifle to the limits of its capability.

The higher magnification levels of Class IV optics are useful for observation and target identification, but can severely limit how a rifle is used. More magnification means  more movement in the scope. Things that you might not notice with a Class I optic, or barely notice with a Class II or III, like your heartbeat or muscle tremors become readily apparent and frustrating from unstable positions. For this reason, Class IV optics are mostly limited to supported positions where these instabilities are mitigated.

I only advise Class IV optics for AR platform rifles if the rifle will primarily be used from a bench or other stable platform in a long-range or precision shooting format. For practical marksmanship or field use, most shooters will be better served by an optic from Class I, II, or III.

Class V Optics: Digital Hybrids


In a way, Class V is the world of science fiction. Class V is a new category of computerized rifle optics. I’m not talking about night vision or thermal sights that overlay a reticle, but rather actual computers that provide real time information to the shooter and/or calculate ballistics on the fly.

I attribute the creation of this class to the Tracking Point system introduced a couple years back. The company has struggled mightily since its introduction, but I predicted back then that the technology would get smaller and cheaper over time. This optic integrates laser rangefinding, a ballistic computer, a digital display, and even includes a fire control system to automatically fire the rifle when the correct point of aim has been achieved. I don’t particularly care for the last bit, but it exists. The shooter is not looking through glass with the Tracking Point scope, but a digital picture that is zoomed in like a video camera. Something to remember with this optic is that if the electronics fail, the whole scope is dead, you cant see through it.


Trijicon has teamed with Kopin Corporation to develop a digital heads up display inside of the ACOG. This has more promise, as losing the digital display still leaves the ACOG in play. This is still in the conceptual R&D stage, so there is not much to say. I would expect that the future is in combining this technology with other classes of optics.

A final note on Optic Combinations


Something I left out is the combining of more than one class of optic on the same weapon to overcome the shortfalls of either one individually. The most obvious example of this is putting a QD or flip-to-side magnifier behind a Class I optic. Another example is placing an offset miniature red dot sight (Class I) next to a higher magnification optic (Class II, III, or IV). At the last SHOT Show, Leupold demonstrated their new D-EVO, which uses an offset 6x scope and mirrors to place a magnified sight picture just below a red dot sight, allowing the shooter to choose which one to use by merely looking downward with their shooting eye.

These are all viable solutions. If you are willing to pay the penalty in increased weight, cost, or complexity to go this route, then go for it.


This is a lot of information. If you were simply looking for what optic you should buy, then I’m sorry. My goal is for you to think about your probably uses, and choose a class of optic that best meets your needs. Once you have decided on that class, then there are many web sites out there that can get you closer to which one you should buy. But at least you know you’re going in the right direction.