Gear, Parts and Accessories

EOTech 512: The Gold Standard of Reflex Sights

EOTech’s Model 512 is America’s leading sight for several reasons. Among them are reliability and reputation; properly setup, but the Model 512 offers so much more. For instance, while building a new AR-15, I decided to top it with the 512. The unlimited eye relief eliminated any worries about parallax. All electronics run the risk of failure; with the addition of a set of flip-up BUIS, I can rest my head at night knowing my new AR will always be action-ready.

EOTech Model 512 right quartering black
The EOTech Model 512’s unlimited eye relief eliminates any worries about parallax.

Another advantage of EOTech’s Model 512 is batteries. This one is really a catch-22 when put up against comparable models from other manufacturers. The Model 512 uses standard AA batteries. The upside to AAs is price and availability. The downside is a larger size and lower power. However, employing lithium batteries in the sight can substantially increase its longevity on a single set of AA batteries. With lithium batteries, you can reasonably expect to get somewhere between 600 and 1100 hours of use; on average, many shooters report averaging somewhere in the 800-hour range. This is less than the five years competing models advertise, and certainly enough time to enjoy plenty of use.

Just to be clear, that would be for continuous use. Some fast reaction forces may need to leave the sight on 24/7. Most of us will shut it off when not in use. For those with the potential of regularly using the Model 512 in life and death situations such as military or law enforcement, set up a reminder to change the batteries on a regular monthly schedule.

After installing the batteries, setup and mounting are simple. The Model 512 features two rubber-coated buttons on the rear of the sight. Press either of the arrow buttons and the sight powers on, retaining any previous brightness settings. Once powered on, you’ll immediately be treated to a large 65 MOA circle housing a 1 MOA dot in the center. Combined, the system makes for fast target acquisition. The larger circle frames the target and the eye naturally seats a single dot on the target. Focusing the subconscious by looking through a single dot is much faster and more reliable than aligning three dots on a target. Proving this is easy.

EOTech 512 reticle red on white
The Model 512 features a 65 MOA circle housing with a 1 MOA dot in the center. Combined, the system makes for fast target acquisition.

Start at 100 yards with a standard half silhouette target. Engage the target offhand with a slow, deliberate rate of fire. Then, repeat the test using iron sights on a fresh target. Note the speed between shots and compare the targets for accuracy. Next, move to the 50-yard line with a bulls-eye style target. Shoot from the bench using the EOTech Model 512 at the first target and iron sights on the second. You’ll quickly begin to wonder whether a magnet is guiding the rounds to the center. At a minimum, you’ll likely discover you are more accurate with a single-dot sight at both short and longer ranges whether shooting from the bench or offhand.

Since my initial testing, I have swapped my Model 512 among multiple platforms. The Model 512 was designed for the standard AR-15 platform—.223/5.56, a low recoil firearm. However, I have mounted my EOTech Model 512 on shotguns, a 6.8 SPC AR and a new 7.62×39 I was testing. It held its zero on each platform.

On a side note, EOTech did not design the Model 512 to work with night vision. The controls face the shooter, so you cannot mount a magnifier and access the controls. This is problematic for some. However, given the accuracy I have experienced—offhand at 100 yards or on moving coyotes—I do not see the need for a magnifier. Likewise, as cool as night vision would be, how many of us really see it in our future?

Magpul AR-15 Back Up Iron Sight MBUS
Magpul AR-15 back-up MBUS folding iron sights make a great addition to EOTech’s Model 512.

Other personal observations to consider when selecting an EOTech sight include the design’s wide field of view. The mount is integral and remains solid magazine after magazine. Any environmental condition, be it rain, snow or mud, the EOTech still performs and will not fog. That also included a cracked lens. A buddy often tells of using the 512 in the sandbox. At some time during a fall down a mountain slope, he cracked the lens; mission requirements dictated they continue their course. Although cracked, he noted no problems using the sight.

If you are a hunter, do not overlook the Model 512. The wide field of view and fast target acquisition are a hunter’s dream—particularly when your target will not hold still. I have never had the opportunity to use the Model 512 for deer, but I have busted a couple of nice double on coyotes with it. After the first dog posts up, the shot is easy; however, that second dog is most often heading for the next zip code. Finding a sight picture and zeroing in on a fast-moving song dog is a real blood boiler when you drop him!

Share your thoughts or experiences with EOTech’s popular Model 512 in the comment section.


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Comments (15)

  1. Well, like anything else there are high and low quality AA batteries. EOTech recommends Energizer AAs for the 512 because of their quality. I’m looking at an 8-pack of Energizer Max Power Seal AAs right now and it has a prominent sign on the front of the package that reads, “NO LEAKS- guaranteed or we will replace your device.” They also claim they have a 10-year shelf life. These eight cost a tiny bit more than your single battery. I have these packs in all my range and hunting/camping bags.

    1. I suppose a no-leak guarantee is a good thing, but it doesn’t help much when you need the thing to work and it doesn’t. Still, it’s great that you’ll get a replacement…. in 6 to 8 weeks. The battery life of my Aimpoints is 3 years, if left on 24/7 (set to brightness level 7 out of 10). I turn my red dots off between uses (unless I forget) so I would expect to do quite a bit better. If you want to talk cost, you have to figure that into the equation. The energy density of Li-Ion is quite a bit better than the 1.5V chemistry. I do see your point, but forgive me if I prefer to stick with a solution that, for a few bucks, eliminates a possible problem. You don’t have to agree, and I hope your solution works well for you. If the low voltage AAs prove over time to be truly impervious to leakage, I’ll have no qualms about using them… but they will need a track record first. I’m anxious to try an EOTech…. just not one that uses AAs.

  2. EOTech makes great CQB sights. The 512 takes up too much “rail” estate. The XPS-2 is smaller. Buy 10 CR123 batteries. They will last 10 years.

  3. WRT “Battery Leakage” in optics, flashlights, GPS units and other items. The Military uses a great many small sized batteries in some pretty expensive devices. There has been for years, a push towards “Wal-Mart available batteries” in Military “hand-helds”. Like the use of AA batteries in the Eotech 512. WRT “installed life”, for the most part (there are always exceptions), if the battery has been installed for 6 Mos, it gets replaced Some Lion Batts can go one year but that is the maximum installed life, regardless if it still operates. What I try to do is place a marking of the Bat Instl Date on my gear, and when it goes into storage…the batteries come out.

  4. I would never opt for a red dot that uses AA batteries. They leak. The lithium versions – the low voltage ones that are interchangeable with alkalines – are more resistant to leaking but not 100%. Having lost a lot of gear, including expensive flashlights, radios and cameras, over the years to leaky alkalines, I now won’t consider anything except the true lithium ion (3.7V) batteries for critical applications. I’ve never had one of those leak. While I currently use Aimpoints, I plan to try an EOTech on my next build – but it will be a model that uses 3.7V lithium-ions. This level of gear is way too expensive to trust to leaky alkaline batteries.

    1. I have two 512’s and initially used the factory recommended Energizer Alkaline in them. I got about 12 months use before they started getting weak and replaced them with the Energizer Ultimate Lithium. I tend to replace AAs periodically (beginning of hunting season) anyway and they are comparatively cheap compared to the button batteries. I’ve only had an alkaline leak once in a flashlight that had gotten buried and forgotten in an old range bag. Change AAs in your 512 like you do change oil in your automobile and you should have no problems.

    2. Hi Jim – I appreciate your comments, but having lost expensive stuff to leaky batteries, the few bucks for a lithium-ion battery is cheap insurance. Regular AAs are unpredictable as to if or when they will leak. $7 bucks or so is a not a lot compared to losing an expensive light, camera, radio, or red dot. That’s my experience talking… I’m sure many will do just as you say and have little or no trouble.

  5. I have some inexpensive red dot sights that work well, but I’m a nut for good iron peep / globe sites. My Mossberg 144 LSA shoots consitent sub 3″ groups at 100 yards even on days like today with gusty 20 – 25 mph winds changing about 50 degrees of aximuth. On the best days with flast light and no wid or mirage it will hoot MOA with irons.

    I’ve heard so much good about Eotech, but a small globe – a Lyman 33 and a good peep with a small O.D. disk would almost certainly serve me better My solution has been superimposed Lee Shaver concentric rings. Unfortunately I need a smaller inner ring but can’t find one. Without a doubt my preference has always been a hollow front. An adjustable front for an AR15 however costs over $125.

    Red dots are nice, but if I am using a reflex or hologram I really want concentric circles and nobody makes them.

    1. Sheldon.. neither the EOtech nor AimPoint..heck any red dot type opt8c..are designed for short range fast target acquisition. They aren’t meant to replace the types of sights your referencing. Long range isn’t really their forte’

  6. I have used the 512 with a 7X detachable/flip up magnifier on an AR platform rifle with a long flat top rail. There was sufficient room between the 512 and magnifier for me to access the rear controls. When your eyes turn 72 you will appreciate a magnifier for 100 yard small targets.

  7. I chose the EOTech EXPS3 here. I prefer it for the shorter profile because I couple it with a 7X flip-to-side magnifier. High quality and dependable configuration for my ARs.

  8. Hands down the EOtech has my favorite reticle for sub 100yrd shooting. Unfortunately it also encourages less committed shooters to be sloppy. Both by using just the 65MOA ring and not getting behind their weapon correctly every time. I notice both first in myself then in dozens of students after i became self concious of the sloppiness.

    A bigger issue for me is reliability. Every generation of the EOT platform has battery box issues. Some fairly common..e.g. tje 5xx line and less comm9n but still statistically unacceptable in the XPS line. Now couple that with HORRIFIC customer dis-service and you have a poor investment given the common retail price point. There is a good reason used EOT’s sell 40% or more below the new price. Wheres as the AimPoint platform retains their value far closer to new purchase pricing.

    Still, subpar battery life (measured in hundreds of hours vs tje AimPoints being measured in 5+years in many models), poor matierials used in the mounting screws and a substandard combat record – talk to any level of military support armorers for more details or just google it – and you arrive at a simple point.

    EOtechs are great for a well funded (see price point) sportsman. But if you have to rely on the optic for a potential life saving or taking need.. there are dozens of better choices for the money.

    Do your own research, please don’t rely on a retailer slanted propaganda piece before spend you time and monwy on any optic!!! I still love the reticle though : )

  9. I have the EoTech XPS2, which uses the smaller 123 battery. It can be purchased with different reticles, but I agree that the one shown in the article is my preference. Other than the smaller size and different batteries, the XPS2 is also more expensive than the 512, which is another consideration. At any rate, I used my EoTech on my tactical shotgun last year to take a 35 lb tom turkey at about 30 yards. It is an excellent site without magnification for tactical shotgun ranges.

  10. The problem with these are they never totally shut off. Also when you frist install the batteries there is an imprint made on the battery when closing the cover. if you remove the batteries for long-term storage they sometimes will not fully install the same again when you go to reinstall them. Other than that they work great except in bright sunlight. I think installing the aftermarket hoods might help.

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