If you have a tactical rifle like an AR-15, it makes sense to buy a tactical scope. However, while red dot sights are the most common option, many shooters like ACOG prismatic scopes for their magnification and battery-free illumination. Which one works for you? Let’s compare these options.
More Reading: Best ACOG Scopes
After reading this, we’d highly suggest reading our full article on the best ACOG scopes for the money, where we list and review the top ACOG optics on the market today.
ACOG vs Red Dot: Which to Choose?
|Feature||ACOG Scope||Red Dot Sight|
|Magnification||1x to 6x, depending on the model||1x only|
|Glass Clarity||Excellent||Good when clean|
|Battery-Powered Illuminated Reticle?||No, uses fiber optics and tritium||Yes|
|Eye Relief||1in to 2.5in||N/A|
|Reticle Type||Etched/varies||Projected/red dot only|
A big reason why people compare red dot vs ACOG sights is that both options come with a fixed magnification setting. However, as we’ll discuss, there are some pretty noticeable differences, meaning that it’s rare to encounter situations where a red dot would be a suitable replacement for an ACOG and vice versa.
That said, each scope has advantages and disadvantages, and you can theoretically use both on the same gun (if you were so inclined). So, they’re not necessarily mutually exclusive.
ACOG vs. Red Dot With Magnifier
One primary advantage an ACOG sight has over a red dot is that it offers higher magnification options. So, to compensate for this discrepancy, you could install a magnifier to your red dot sight to give you a similar viewing experience.
The benefit of using a magnifier is that you can switch back and forth between 1x and a higher magnification setting, depending on the situation. The downside, however, is that you won’t get the same image quality or clarity as you do with an ACOG sight.
Overall, red dot sights are designed for fast target acquisition and reflex shooting, not precision targeting. So, even with a magnifier, the glass on the scope won’t be as good as what you’d find on an ACOG. Plus, it doesn’t come with a diopter, so you won’t be able to adjust the image to compensate for visual impairments like astigmatism.
ACOG stands for Advanced Combat Optical Gunsight, and it refers to a line of prismatic scopes made by Trijicon. So, while other prism scopes may claim to be an “ACOG,” the designation is proprietary to this brand.
Also, the “combat” part of that name is not an exaggeration. ACOG sights are deployed with soldiers in active combat, so they’re built to handle the toughest terrains and scenarios.
If you purchase an ACOG, you know it will be shockproof, fog proof, waterproof, and even blastproof. (Reference 1: ACOG scopes)
- Extra Durable Housing – Trijicon ACOG scopes are used in the field, being deployed in active military campaigns and law enforcement situations. So, if the housing is good enough for actual combat, it can handle anything you might encounter while hunting or target practicing. An ACOG sight can handle vibrations, drops, and almost all kinds of wear and tear.
- Multiple Magnification Options – Unlike most red dot sights, Trijicon ACOG scopes can come with a fixed magnification between 1x and 5.5 or 6x. A higher magnification setting makes the scope better for mid-range hunting and targeting, but they can be harder to use for close-quarters combat.
- No Battery Necessary – Instead of a battery, an ACOG sight uses a fiber optic cable running along the top edge. This cable absorbs sunlight and uses it to illuminate the etched reticle. In low-light or nighttime situations, as the reticle is coated with a small layer of radioactive tritium, it glows in the dark.
- Accounts For Astigmatism – Astigmatism is a condition that can lead to blurry vision, and it can be a noticeable problem with a projected scope like a red dot sight. Since ACOG sights use prisms, you can adjust the sight picture with a diopter to compensate for visual impairments.
- Excellent Glass Clarity – When using a Trijicon ACOG scope, you’ll notice the image clarity is much better than a red dot sight. The brand uses high-quality glass and prisms to improve the sight picture contrast, so it’s easier to spot your target.
- Multiple Reticle Options – Because ACOG sights use a magnified optic, Trijicon offers a wide array of reticle designs. Each one also comes with a bullet drop compensator so you can aim at longer distances more accurately. Overall, you can choose the reticle you like best instead of settling for a red dot sight.
- More Expensive Than Red Dots – When compared to cheaper red dots, Trijicon ACOG scopes are far more expensive. However, given the quality of an Advanced Combat Optical Gunsight, it’s not like you’re wasting money.
- Heavier Than Red Dots – Part of what makes a red dot sight so versatile is its lightweight compatibility. Since Trijicon ACOG scopes are relatively heavy, you need to mount them to rifles only, even though they’re shorter than most other tactical scopes.
- Short Eye Relief – One side effect of using a prism is that it shortens the eye relief. In some cases, you have to mount the scope further back on the gun so you can get a clearer image.
How Do They Work?
Trijicon ACOG sights are prismatic, using internal prisms instead of an objective lens array. Prism scopes work similarly to binoculars, refracting the light to magnify the image. Although these sights don’t have variable zoom settings, they often come with a diopter, so you can adjust the prism position to make the image clearer.
ACOG scopes also offer illumination from a battery-free light source. A fiber optic cable sits on top of the scope and absorbs sunlight, which it then uses to create a bright picture inside the scope. The brighter the sun, the more illumination.
For nighttime shooting, an ACOG scope uses tritium that glows in the dark. So, these scopes are night vision compatible, although you have to supply your own goggles.
Red Dot Scope
As the name suggests, a red dot sight is a scope that uses a red dot as the reticle. Red dot optics are not complicated, as the lens only magnifies your image by 1x, making an object 100 feet away look one foot away.
Multiple companies make red dots, and they’re incredibly easy to use in various situations. In fact, some shooters will mount red dot optics to enhance iron sights or in addition to a magnified optic.
- Compact and Lightweight Design – Red dot sights are so small and easy to mount that you can often add one to your gun, even if you have a scope attached.
- Deployable for Any Firearm – Red dots are so light and short that you can put them onto any firearm, including pistols, rifles, and even shotguns. (Reference 2: Red Dot Sights)
- No Need to Zero Out – One of the problems with magnified optics is parallax, which can make the reticle off-center. With a red dot sight, you’re only getting a true 1x magnification, so there’s no need to “zero out” the scope with each use. Like iron sights, a red dot is accurate 100 percent of the time.
- Affordable – If you’re looking to add a scope to your firearm, you can expect to drop $1,000 or more for a high-quality model. However, red dot sights are much cheaper, making them suitable for shooters of all skill levels.
- Easy to Mount – If you’ve ever mounted a long-range scope before, you know you need the right mounting hardware. On average, a red dot sight is much easier to install on your firearm, even if you’re new to the process of mounting scopes.
- No Extra Magnification Options – While a 1x sight is ideal for close-range shooting and home defense, it’s not ideal for hunting or mid-range target practice. So, you get what you get, and that’s it.
- Battery Can Die – The red dot reticle is projected on the lens, so if your battery dies, your reticle disappears.
- Limited Reticle Options – A red dot sight only has the one reticle type, so you can’t choose any different ones based on your preference.
- Blurred Reticle For Shooters With Astigmatism – If you have astigmatism, it’s hard to find reticle clarity as the red dot may look smeared or distorted. If you still want to use a red dot, opt for a green dot reticle.
How Do They Work?
Red dot sights use very basic technology to project the reticle onto the glass. First, the lens is coated in a material that only reflects red (or green) light.
So, the projector fires a beam of pure light at the glass, but only red bounces back, making the dot visible to you. Interestingly enough, if someone was looking through the other side of the scope, they wouldn’t see anything.
Because it’s a red dot projection, it needs a power source to turn on. Fortunately, shooting a beam of light doesn’t require much energy, so a single battery should last for several hundred hours before dying.
Another point regarding red dot scopes is that the glass is slightly curved, giving you a true 1x magnification. So, objects within 100 feet or so will appear closer, allowing you to pinpoint your target quickly and accurately.
FAQs About ACOG vs Red Dot Scopes
Are ACOG scopes legal?
Yes, ACOG scopes are legal to buy and own in the United States. Although these scopes are actively used in the military, there are no laws against civilians owning and using them.
What range is ACOG good for?
The range of an ACOG is good for close-quarters combat and mid-range hunting, depending on the model. As a rule, 1x magnification is suitable for accurate shots at 100 yards (91.4 meters) or less, so a 2x scope is good for 200 yards (182.8 meters), and so on, and most ACOGs are between 1.5-5x zoom.
What is a red dot scope good for?
Since a red dot sight only offers 1x magnification, it’s only suitable for close-range shooting, such as target practice or home defense. Realistically, the ideal range is 100 yards (91.4 meters) or less.
Are ACOGs obsolete?
No, ACOG sights are not obsolete. In fact, the Trijicon ACOG is still deployed in active military combat situations.
Is red dot an ACOG?
No, red dot sights are not the same as ACOG sights. Red dots are designed for reflexive firing and fast target acquisition, while ACOG sights are better for precision and mid-range shooting.
Why use an ACOG scope?
People use ACOG scopes because they are some of the most reliable and durable on the market, making them ideal for most close and mid-range firing needs. ACOG scopes use prisms instead of lenses, giving them sharper images and excellent clarity with an etched reticle.
- Trijicon, The History of the Legendary ACOG. Retrieved from https://www.trijicon.com/our-story/trijicon-acog-history
- Victor Masters, Why this firearm manufacturer takes a different approach to red dot sight systems for law enforcement. Retrieved from https://www.police1.com/police-products/firearms/articles/why-this-firearm-manufacturer-takes-a-different-approach-to-red-dot-sight-systems-for-law-enforcement-Te7YRWKpNfb55L8l/
I have been writing firearms and outdoor material for over 50 years to date. I have hunted across the world, including Russia, and a great deal of time professional hunting in Australia. I currently live in the American West and hunt all across the Black Hills of South Dakota and the Big Horn Mountains. I have specialized much of my work as a load developer in shotguns and rifles. I have run a small company that builds suppressor barrels of my design and load tests for writing purposes and consulting. My commercial names include Ballistics Research & Development / Metro Gun Systems TM.
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