Whether you’re hunting, shooting competitively, preparing to defend your home against intruders, or facing a catastrophic bug-out situation, it’s essential to be able to quickly acquire and accurately hit targets with your weapon of choice. Much of this comes down to training, but technology can also give us an advantage in this area. Modern optics provide an easy-to-use alternative to iron sights. Specifically, non-magnified dot sights have become ubiquitous in the firearms world as a result of their versatility for a variety of weapons and lighting conditions.

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These days, the majority of home defense guns and survival rifles you’ll come across will have some form of dot sight in addition to backup iron sights. Even on carry handguns, they’re continuing to become increasingly popular — in a poll we posted last year on this site, 72 percent of readers said they have “positive” or “very positive” feelings about running dot sights on their carry pistols.

The caveat to dot sights is that they can easily cost $500 or more, and while there’s no shortage of low-budget options on the market, many of those airsoft-grade sights are fragile, poorly-built, and/or unreliable (the last things you want on a weapon that you might need for self-defense). Finding a middle ground between price and dependability can be tricky, especially when you’re looking for a sight that doesn’t skimp on features.

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Holosun recently released the HE510C-GR as part of its Elite green dot sight series. It’s an open reflex sight, meaning that it uses a dot projected by an LED onto a thin reflective lens, rather than the cylindrical design of closed tube sights. This is intended to provide maximum field of view and minimal reduction of ambient light. MSRP for the sight is $388, but it’s currently available from various online retailers for $330.

The Case for a Green Dot

In the past, virtually all dot sights used red aiming points, and they’re still the industry standard today. However, green dot sights have seen a surge in popularity lately for various reasons. We’ll admit that some of this is an aesthetic trend, motivated by users wanting something new and different. But there’s more to it than that.

This chart from the UK National Physical Laboratory shows the spectral response of the human eye.

This chart from the UK National Physical Laboratory shows the spectral response of the human eye.

The obvious purpose of any sight is to provide a clear, high-visibility aiming point. From a purely scientific standpoint, the human eye is most responsive to colors in the green portion of the visible spectrum, meaning that a green light will be perceived as brighter than a red or blue light of equal power. As a result, Holosun says its green diode is “as much as 4 times more efficient” than its standard red diode, especially at high brightness settings.

A green LED near the back of the optic projects the dot onto the lens.

A tiny green emitter near the back of the optic projects the dot onto the lens.

Of course, we don’t live in a world of black and white, so in a practical setting the technical advantages of a green dot may be more limited. Much of it comes down to the environments where you’ll be using the weapon — a green dot may offer superior contrast in drab urban environments, while it may get lost more easily against the bright green backdrop of a forest. Personal preference is also a consideration, so you should take a firsthand look at both dot colors and see which works best for you.

If a green dot just isn’t your thing, Holosun offers an HS510C red dot reflex sight that offers the same design and features as the HE510C-GR.

Holosun HE510C-GR Elite Features

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We got our hands on a sample of the HE510C-GR, and decided to take a closer look at its viability as a more-affordable choice in the dot sight market.

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Right off the bat, the packaging caught our eye with its prominent “green dot sight” label. The flamboyant font choice seems out of place, but we soon overlooked this and opened the box. It contained the following items:

  • Sight with included quick-detach mount
  • Adjustment/battery removal tool
  • Spare battery tray with O-ring and screws
  • Torx wrench
  • CR2032 battery
  • Micro-fiber lens cloth

As we said before, this is an open reflex sight which uses Holosun’s “Green Super LED” to project either a 2-MOA dot, a 65-MOA circle, or both onto the lens.

The HE510C-GR can display a dot, circle, or both simultaneously.

The HE510C-GR can display a dot, circle, or both simultaneously.

The optic’s controls are very straightforward, with rubberized “+” and “-” buttons on the left side. The adjustments are as follows:

  • Short presses of “+” or “-” adjust between 12 dot brightness levels.
  • Holding down “-” cycles between the three dot/reticle options mentioned above.
  • Holding down “+” until the reticle blinks toggles between Automatic and Manual modes — more on this feature below.
  • Holding down “+” for 10 seconds adjusts auto-shut-off timer setting.
  • The light can also be manually turned off by pressing both buttons, and turned back on by pressing either “+” or “-“.
  • Elevation and windage can be adjusted by turning a pair of screws with the included adjustment tool. Each click is 1/2 MOA.

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The HE510C’s body is constructed from 6061 aluminum, but it features an additional titanium shroud to protect the recessed lens from impacts to the top or side. The base of the sight features a quick-detach Picatinny rail mount, which includes a locking lever and a Torx screw to adjust the clamping force.

The gap between the body and titanium shroud protects the lens from impacts.

Power comes from a single CR2032 lithium-ion coin-cell battery. This is installed by loosening the two Torx screws on the battery tray, prying it open with the included tool, and reinserting the tray with the battery. Holosun claims a maximum battery life of 50,000 hours with the dot, and 20,000 hours with circle and dot.

Looking down from above, you’ll notice the HE510C features a second power source: a solar panel. This serves two purposes. First, it can fully power the optic using ambient light from the sun or indoor light sources — if these aren’t bright enough, it draws some or all of its power from the battery instead. Second, it acts as a light sensor to measure your environment and adjust dot brightness accordingly in automatic mode.

Automatic Mode

In its default automatic setting, the HE510C will monitor ambient light levels and increase or decrease the dot’s intensity to produce optimal visibility. This ensures you don’t end up looking at an overwhelmingly-bright dot in a dark room, or struggling to spot a dim dot on a sunny day. Within auto mode, you can adjust the brightness range to 8 levels.

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If you prefer, you can also set the optic to manual mode with 12 brightness levels (10 for daylight and 2 for night vision). The sight has a memory function to remember these settings.

Shake Awake

To further extend battery life, the HE510C has a “Shake Awake” motion sensor which can detect movement and immediately turn the sight on. It will then remain on for 10 minutes (default), 1 hour, 12 hours, or indefinitely, depending on the auto-shut-off timer setting you’ve selected.

Our Impressions

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After removing the sight from its box, we installed the battery. Even with the screws removed, the battery tray seals tightly to keep out water and dust, so prying it open with the included tool was a little tricky. We took our time to avoid scratching the finish. Luckily the extremely long battery life means we probably won’t be replacing it again for a decade.

Thanks to the included quick-detach mount, installing the HE510C on a Picatinny rail is easy. Just depress the release button at the end of the locking lever, swing the lever open, and place it on the rail. The Torx adjustment screw needed to be loosened a few turns before the mount would clamp snugly. This mount is a big plus, since adding QD functionality to many other dot sights means spending an additional $100 on a separate QD mount or riser.

The HE510C’s mount places it at absolute co-witness height for standard AR sights, so it aligned nicely with the A2 fixed front sight and Magpul MBUS flip-up rear sight on our S&W M&P-15 Sport II test gun.

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Learning the controls was simple — we simply left the optic in its default automatic setting with a 10-minute shut-off timer, and increased the brightness setting slightly. The Shake Awake feature is very sensitive, and the sight activated reliably as soon as we picked up the gun. If you’re keeping this sight on a truck gun, you’ll definitely want to disable Shake Awake to avoid draining the battery with every bump in the road.

The green dot is clear and easy to track against a variety of backgrounds, even in intense midday sunlight. The dot and ring both exhibited good sharpness.

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We tested the automatic brightness feature by walking between light and dark rooms — we were pleased to see the dot adjust on its own with barely a second of delay. One issue with this system is that it measures ambient light directly above the sight, not in front of the sight. This means that if you’re aiming from a dark room into a fully-lit one or using a weapon-mounted light to clear a dark hallway, the dot will wash out and become difficult to track. Manual adjustment alleviates this, but requires fiddling with the controls.

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Holosun claims this sight is “parallax free” but the reality is that all dot sights have some amount of parallax (i.e. perceived movement of the dot when you move your head — see this video for a demonstration of the effect). Fortunately, we didn’t notice any substantial parallax during our testing, so this sight is good-to-go on that front.

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Zeroing was straightforward, and we didn’t notice any substantial point of impact shift after putting rounds downrange at 50 to 100 yards with our M&P-15. Holosun says the sight can be used on shotguns, so we mounted it on a Remington 870 Tactical and ran through some 00 buckshot to see how it held up. Despite the harsher recoil, the dot didn’t wander.

Conclusion

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Considering our previous experiences with inexpensive red dot optics, we were interested to try this Holosun, considering its full list of features and affordable price. We were pleased to find that it offers solid build quality and reliability at a price that’s hundreds less than a comparable setup from other big-name companies.

Is it capable of taking years of hard use or surviving a house fire? Only time will tell, but our initial impressions of the HE510C-GR Elite have been positive. For the record, Holosun offers a limited lifetime warranty against defects on the housing or lens, and a 10-year warranty on the illumination system (this applies to Holosun’s Elite optics only; Classic optics have a 5-year lens warranty and 3-year illumination warranty).

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As for the topic of green dot versus red, color preferences will vary from one person to the next, but we found the Elite green dot was easy to pick up against most backgrounds. For home-defense or urban applications, we slightly prefer the green dot. Again, if red is your personal preference you can check out this sight’s red-dot counterpart from Holosun.

Overall, we’re glad we tried the HE510C, and it surpassed our expectations. Admittedly, it’s not going to make other more-costly optics totally obsolete, but it’s a dependable sight that offers good value for the money.

For more information on Holosun products, go to Holosun.com,

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