Red dot optic vs. LPVO: Which is better for your AR-15?

The AR-15 has earned its place as America’s rifle over the past 50-plus years. Multiple improvements have been made to Eugene Stoner’s original design, but his concept of a lightweight, reliable, accurate rifle or carbine made from aluminum, steel, and polymer is still a home run for today’s sportsmen and women, shooters, competitors, and hobbyists. One major update to the platform over the past 3 decades or so is the transition from iron aperture sights to optics, and nearly all AR-15s now come with picatinny rails atop the receiver to facilitate the easy mounting of optical sights. Iron sights, if they are included at all, are generally called Back-Up Iron Sights, or BUIS, and many people don’t even install them on their ARs, since optics have become so reliable and their advantages are so obvious.

For an AR intended for duty, competition, defensive, or general use, there are two major schools of thought for the best and most versatile optics: Red dots or Low-power Variable Optics (LPVOs). The debate between these two choices has raged for decades and will likely continue for decades more, but let’s see if we can provide some information to help you narrow down your choice to the one that might be perfect for you. (Hint: the ideal setup for most people might actually be neither, but you’ll need to scroll down to the end to learn about that.)

What is a red dot optic?

A red dot optic has become a somewhat generic term for a (usually) non-magnified, (usually) electronic, compact sight for firearms. Named because the simplest (and original) styles simply projected or reflected a red LED dot into the center of the optic’s viewing window, red dots today may actually utilize red, green, yellow, or other colors of reticles and dots. However, when discussing them generally, most firearms-knowledgeable people will accept calling this category of sighting systems red dots.

There are generally considered to be 3 major types of red-dot sighting systems:

• Reflex: The term reflex is usually stated to be a shortened form of reflective or reflector, but today it may also refer to the reflexive, natural shooting capability this type of optic allows compared to iron sights, since it obscures much less of the target. This type of sighting system was first invented in 1900 and variations were widely used on anti-aircraft guns and other weapons during World War II. However, for our discussion today, modern reflex/red dot sights used on rifles and other firearms optics usually use an LED (light-emitting diode) to project an aiming point, commonly a simple dot (and usually red), onto the lens that the shooter looks through. The lens is coated with advanced materials and reflects the image of the LED (sometimes tritium and/or fiber-optic) light into the shooter’s eye. This is the first modern rifle red dot style that hit the market in the early 1980s, and is still the most popular overall. A good example of a reflex-style red dot for the AR-15 is the Aimpoint Micro H-2 ($699 with included AR mount).

• Holographic: Technically known as holographic diffraction optics, holo sights use a laser to illuminate a hologram of a reticle image that is recorded 3-dimensionally onto holographic film when the sight is manufactured. The reticle image is part of the optical viewing window through which the shooter looks, and is lit up by the collimated laser light bounced/reflected from a holographic grating. This all sounds extremely complicated, and it is, but the upshot is a holographic sight basically seems like magic when you use it. The image of the reticle appears to hover in space in the viewing window, and you can move your head pretty much anywhere around the sight… as long as you can see the reticle, you can usually hit what you aim at, with minimal (if any) parallax effect. The most common type of holographic reticle today is any variation of the circle dot, which includes a central dot or dots surrounded by a larger, often segmented outer ring that helps direct your eye to the target. EOTECH is the most well-known brand for holographic rifle sights, with the EXPS2 ($679) likely being the most widely used model over the past few years.

• Prismatic or prism: A prism sight is sometimes considered a separate category, and not a true red dot, but the concept and footprint are so similar today that we’re including prism sights in this group. A prismatic sight is constructed similarly to a standard rifle scope, but with fewer lenses. The name comes from the prism that is used to flip the reflected image onto the viewing lens, which would otherwise be upside-down. Most prism optics have the reticle etched onto the glass, which can be a huge benefit if your batteries fail. They may or may not be illuminated, but most modern prism sights have that option. Prism sights are fairly simple in construction, and the nature of the glass makes them very durable. Additionally, many prism sights allow 2X or 3X (or more) fixed magnification, so if you prefer a little larger view of your target but want to keep your optic very simple, a 2X prism red dot might be the one for you. A well-regarded prism sight for modern AR use is the Primary Arms Cyclops Gen II ($199).

Red dot sights may work differently, but the good ones essentially result in a similar shooter experience, with some possible differences in reticle preference and battery life.

What is a LPVO (low-power variable optic)?

An LPVO is a compact rifle scope intended for dynamic situations where the shooter may need to engage targets at very close ranges, as well as identify and potentially engage targets at ranges of 300-400 yards or more. The Low Power in the name refers to the magnification level of the scope, which usually starts at 1x (actually just over 1x in most cases), and with the twist of the magnification ring, goes up to 4x, 6x, 8x or more. The concept of a low-power variable rifle scope goes back to the 1920s, but in modern combat the first LPVO that defined this new genre of optic was the Schmidt & Bender CQB Short Dot 1.1-4 x 20mm scope, which was fielded by some Special Forces teams in the mid-to-late 1990s. The Leupold MK4 CQ/T 1-3x was also very well regarded during that period, as was the Trijicon AccuPoint 1-4x. After 20-plus years of development, we have LPVOs that are stretching the definition of Low Power, with magnification up to 10x (or more!). The Vortex Razor HD Gen III 1-10×24 ($3,999 MSRP) is probably the overall gold standard for what’s possible with today’s LPVOs. That’s a lot of money, but the performance is undeniable. However, there are excellent budget-tier LPVOs like the Primary Arms SLx 1-6, a first-focal-plane scope with the excellent ACSS Raptor reticle for under $400.

Why would you choose a red dot optic for your AR-15? (Pros and cons)

Let’s review the advantages and tradeoffs of choosing a red dot for your rifle or carbine.

Advantages of red dot sights

• Red dot optics are extremely lightweight and compact compared to LPVOs. The Aimpoint H2 with standard AR mount weighs 8.6 ounces, but many lightweight mounts are available. The optic itself weighs only 3.3 ounces. Primary Arms’ Cyclops Gen II weighs 5.5 ounces without the mount, and around 7.5 ounces with the basic mount installed. EOtech’s EXPS3 weighs 11.2 ounces with the included mount. Mini red dots are even lighter. For comparison, the Primary Arms SLx 1-6 LPVO mentioned above weighs 17.6 ounces without a mount, and the Vortex Razor HD weighs 21.5 ounces without a mount. The lightest quality LPVO mount weighs 5.48 ounces, and most weigh 8-10 ounces or more. Red dots also take up less space on top of your rifle compared to a longer, tube-like LPVO.

• Red dots have effectively infinite eye relief and huge eye boxes. You can place your red dot optic on a forend rail and still see the dot perfectly well. You can move your head nearly anywhere around the back of the optic and the view to the dot or reticle is only limited by the sides of the optic housing. This allows shooting from unconventional positions, side-lying prone, angled through barricades, etc. without issue. It also means you can acquire a flash sight picture and deliver a first shot on target extremely quickly with a red dot.
• Red dots are less susceptible to the effects of parallax. Many claim that red dots are parallax-free, but that’s not exactly accurate. There may be some shifting of the dot or reticle on the target as you move your head around the eye box, but compared to many scopes, including many LPVOs, parallax will likely not be any significant problem with a quality red dot (including prism optics or holographic sights).
• Red dots offer a true 1x view through the optical window. Since you’re essentially just looking through flat panes of glass (in the case of reflex and holographic red dots), there is no magnification at all, and no warping of the image around the edges of the optic glass.
• Red dots are generally less expensive than LPVOs, though the cheapest LPVOs can be had for less than some quality red dots. The most expensive red dot won’t even come close to the price of the most expensive LPVOs, which can surpass $4,000.
• Red dots are exceptionally durable. Multiple destruction tests and equipment torture protocols have shown that quality red dot optics can survive incredible amounts of abuse.
• Basic red dots are extremely intuitive and simple to use. Look through the window, see the dot, put the dot where you want the bullet to go, press the trigger.

Downsides of red dot sights

• No magnification. Good shooters can make regular hits on torso-sized targets out to 300 or maybe 400 yards using an un-magnified red dot, but the limits of accuracy at those ranges are determined by the limits of the shooter’s eyesight. Target identification becomes very difficult the further out you go.
• Precision shots are more difficult. Most red dots have a 1 MOA dot or center reticle, and many have 2 MOA or larger. At 300 yards, a 2 MOA dot covers 6 inches of the target with the reticle alone.
• Electronics and batteries can fail. Reflex-style red dots and holographic sights usually depend on batteries, LEDs, or laser diodes to project/reflect the reticle for aiming, and batteries, solar cells, fiber-optic rods, or tritium vials must power those. All of these are potential points of failure. An EOtech XPS3 has a battery life of around 1,000 hours on setting 12, while an Aimpoint T-2 offers 50,000 hours (over 5 years) of constant-on battery life. But when the battery dies, so does your reticle. Prism sights offer a solution for this, as noted above, but there may be tradeoffs in eye relief, eye box, or lens performance around the edges.
• People with astigmatism or other eye issues sometimes find red dot reticles impossible to use. The dot may be fuzzy, it may bloom, it may look like a slash instead of a crisp, round dot, or it may even present itself as 3 or 4 separate dots, depending on your eye. Prism-style red dots often mitigate these issues for people with astigmatism, but it’s something you should be aware of.
• People who wear prescription/corrective lenses may find red dots unusable either with or without their lenses in place, depending on the situation. For example, someone might not be able to focus on an EOtech reticle without corrective lenses. There’s no provision to focus the optic itself with a red dot.

Why would you choose an LPVO over a red dot for your AR-15? (Pros and cons)

Now that we’ve gone over the fundamental benefits and caveats of red dot optics, let’s discuss LPVOs in the same fashion.

Advantages of LPVOs

• LPVOs are far more versatile compared to red dots. When used properly, an LPVO allows near-1x performance up close, with the additional benefit of near-instant magnification changes when needed to see further distances clearly. Making accurate hits at 500 yards is essentially impossible for most shooters with a red dot, but is quite doable with a quality rifle and LPVO setup. To approach this capability, a red-dot shooter would need to add a flip-up magnifier behind the red dot (see the bottom section below), and even then the quality of the image (and magnification level) would likely suffer compared to a good LPVO at extended ranges.
• LPVOs typically have very useful reticles, including hash marks at a minimum, and often wind holds or other bullet-drop compensating features. This further enhances a good shooter’s ability to place accurate fire on targets at extended ranges compared to red dots, even those with BDC reticles.
• Target identification is greatly enhanced by the increased magnification afforded by an LPVO. Even a 3x or 4x optic provides vastly improved levels of information about a target and its surroundings compared to a 1x red dot. If most of your shooting is going to be past 100 yards, and/or most of your targets are going to be small, an LPVO is the obvious choice.
• Precision shots are much easier. Most LPVOs today have optionally illuminated reticles to enhance shooting at speed or in low-light conditions, but the illumination or Dot feature can be shut off, typically leaving a clean, fine reticle that allows very accurate shooting when required. This reticle also remains if your LPVO’s battery dies, or if the optic is simply not turned on.
• The ocular lens (rearmost lens) of the LPVO can be focused to the shooter’s eye in almost all cases. This allows shooters who may not have their corrective lenses with them to adjust the ocular lens to their eye and still be able to functionally use the optic. This may not be the case with some people using red dots, for whom a reticle may appear as a mere cloud or blur without their lenses in place. There’s no provision to focus a red dot optic, but there is for an LPVO.

Disadvantages of LPVOs

• Weight and bulk. The majority of good-quality LPVOs weigh at least a pound, and the mount adds another half pound or so (5.48 ounces at the minimum). We know from experience that the Trijicon AccuPower 1-8x LPVO in a Bobro quick-detach cantilever mount weighs a porky 37+ ounces, or well over 2 pounds. All that top-heavy weight can get annoying, particularly if you’re running and gunning during a battle or a multigun competition.
• Few LPVOs are actually a true 1x magnification on the lowest setting. Some people strongly claim that the nature of an LPVO’s construction with its multiple lenses makes it impossible to ever achieve a true 1x. This may or may not be an issue for you, but if you’re bothered by the image through the optic not exactly aligning with the image outside, then an LPVO is likely not the choice for you. Again, many of the top LPVOs today claim to be true 1x capable, and many users have stated they can’t detect any magnification. But it’s something you should be aware of.
• Eyebox and eye relief are limited. As with any multi-lens scope capable of magnification, eye relief (the distance your eye needs to be placed from the ocular lens to prevent shadowing) and eye box (the lateral flexibility allowing you to see the reticle and target clearly if your eye isn’t perfectly aligned behind the scope) are potential issues. Typically, as magnification goes up, proper eye relief becomes more critical, and eye box diminishes. This is one of the primary downsides of this type of magnified optic, and many shooters who are used to shooting 1x red dot style sights have difficulty adjusting to an LPVO. If you are frequently shooting on/around/through props or from unconventional shooting positions, a red dot is the clear preference as far as a forgiving eye box is concerned.

• Parallax can be an issue with some LPVOs. If you strap down the rifle and look through the optic, moving your head from side to side, the placement of the reticle relative to the target image should not change, if parallax is accounted for accurately. If the reticle moves relative to the target background as your eye moves, your rounds may not impact where you expect them to.
• Speed of sight acquisition is almost always slower when using an LPVO, even when comparing an LPVO set to 1x with a red dot. The tubular nature of the LPVO with its multiple objective/focal/ocular lenses, means that your cheek weld and eye placement simply must be more accurately located directly behind the scope than is necessary for a quick sight picture through a red dot. A top-tier shooter who is well-practiced with an LPVO might give a top-tier red-dot shooter a run for their money, but in general, for most people, the red dot will be faster to acquire and enable a faster first shot.
• Cost is a significant factor. There are good deals to be found in LPVOs, but functional, durable red dot sights can be found for well under $100. In practical head-to-head evaluations, it would be difficult or impossible to tell the difference between some inexpensive red dots and some of the most expensive ones. With LPVOs, you definitely can expect to pay a lot more than you will for a red dot if you want the best equipment available. The nature of the multiple lenses required for an LPVO, and their required quality as far as clarity, precision, and light transmission, drives up the price. The manual adjustment mechanisms inside an LPVO also add to its price.
• If ultimate durability is a primary factor, then an LPVO will likely not be your first choice. The nature of how an LPVO is constructed simply makes it more susceptible to breakage and loss of zero during rough handling or impacts, when compared to a quality red dot.

What’s the Goldilocks setup for a general-purpose AR-15?

As you consider the pros and cons of red dots and LPVOs, you need to weigh your priorities and your situation against the advantages of each optic. However, for most people, a good general recommendation (hinted at in the intro above) is a third option: A red dot with a quality flip-up 3x or 4x magnifier mounted behind it. This allows many of the benefits of the increased magnification of an LPVO, while retaining all the benefits of a true 1x red dot when the magnifier is flipped to the side. The weight is increased a little, and it uses up some rail space, but most magnifiers and red dot combos are roughly the same length of an LPVO on a common cantilever mount and may even weigh less. A red dot plus magnifier can be the sweet setup for a fighting/defensive or competition rifle in a dynamic environment where you may have to adjust to both rapid close-in targets and more distant ones. If you decide to go this route, make sure your red dot’s reticle looks good to your eye under magnification, and make sure you don’t go super cheap on the magnifier because the quality of the glass/lenses can be pretty bad on some of them.

And always remember, whatever rifle/carbine and optics setup you choose, keep your firearms secure in a quality gun safe from Liberty. Shoot safely!