The HS510C — Holosun’s Squared-Off Red Dot

When it comes to red dot and reflex optics, I find the open square-style windows to be my overall preference. When I saw the HS510C, I took an immediate interest. The design, features, and prices begged me to pick it up. I was impossibly curious about what kind of quality I could expect from a red dot with a sub-350-dollar price tag. 

HS510C Specs and Features 

The Holosun HS510C is a feature-filled optic. This little fellow has a side-loading battery compartment as well as a solar failsafe. The battery lasts for 50,000 hours on the medium setting. If the optic is unmolested for an extended period, the shake awake technology automatically shuts it off. When the optic is jostled, it fires back up and is ready for action. 

Holosun HS510C red dot review
The HS510C is perfectly designed for modern rifles.

The HS510C features three reticles, a 2 MOA dot, a dot and 65 MOA circle, and a 65 MOA circle by itself. We’ll talk for literal paragraphs about these three later. Twelve total brightness settings occupy the HS510C, broken into ten daylight settings and 2-night vision settings. 

The optic weighs 4.94 ounces and features an aluminum and titanium hood for durability and weight savings. The window is .91 inches tall and 1.26 inches wide. If you want an absolute co-witness, then the HS510C provides that. 

HS510C In the Field 

Hitting the field, I equipped the HS510C to my Bullpup Scorpion. I figured the Bullpup was space-age enough to warrant a space-age looking optic. We know an optic works with a battery, but I wanted to test how well the solar panel worked, so I left the battery tray empty. 

Holosun HS510C red dot solar panel
It’s all about that solar panel.

Admittedly as I turned the optic on, I got a low battery indicator. Throughout testing, this indicator came on every time; clouds blocked the sun a bit. The reticle never died during my initial testing, and it merely blinked occasionally to let me know what was what. 

I was doing a bit more shooting and left the HS510C in the sun for a bit as I worked with other firearms. When I returned to the HS510C and Scorpion, the battery had received a decent charge because the battery indicator didn’t flicker the rest of the day. 

Zeroing was a hassle, mostly because my model came maxed out to the left. It took forever to get on paper, but once I figured it out, everything went normal. I zeroed at 25 yards and confirmed at 50 and then 100 yards. 

Reticle Versatility

Remember when I mentioned we’d have paragraphs and paragraphs worth of information on the reticles? Well, we have reached that portion of the review. 

The 65 MOA circle and dot reticle are convenient for several reasons, including longer-range engagements.

100 Yards with a 9mm is a bit of a challenge. It’s about a foot of drop at this range. I used the reticle to compensate for the range and decently estimate the drop. 

Holosun HS510C 2 MOA red dot seen through reticle.
The small 2 MOA dot is a battery sipper that’s precise.

I placed the dot at the head level of a VTAC target and knew the round would land between that dot and the bottom of the reticle. This quick adjustment allowed me to land several successful shots into the bad guy’s upper torso. It turns out 9mm causes some significant heartburn when placed appropriately. 

Holosun HS510C 65 MOA circle and dot.
The bigger reticle is more versatile.

You can also use the reticle for range finding. The size of the circle is picked on purpose. 65 MOA wasn’t a random number they chose. At 100 yards, the 65 MOA circle equals the average height of a man. If a man-sized target fills the circle, it’s at roughly one hundred yards. 

When a man-sized target fills from the dot to the bottom of the reticle, he’s 200 yards out. If the target fills the lower two-thirds of the reticle, he’s 300 yards out. When the target fills halfway from the bottom of the ring to the dot, he’s four hundred yards out. It’s not perfect but is functional enough in a pinch. 

Holosun HS510C side view logo.
I like everything but this giant logo.

At super-close ranges, we know we run into mechanical offset, and our rounds will hit low. The 65 MOA reticle allows us to use the bottom stadia as an aiming point to compensate for this offset. Russian hostage negotiations involve a body bag for the hostage and hostage-taker, but you won’t need to do it Russian-style since you can make super precise close-range shots. 

What about the other two reticles?

If you find the optic too crowded, then swap to the 2 MOA red dot. The 65 MOA circle only is an excellent close-range combat option. Fill the circle with the bad guy and pull the trigger until the bad guy is no more. The dot is just a more refined option for longer range shooting. 

Options—you get lots of them with the HS510C.

Through the Lens of the HS510C

The HS510C presents a crystal clear reticle in the circle and circle-and-dot combination. The dot alone actually washes out a bit at higher brightness levels. Speaking of, this thing can get punishingly bright. Brighter than I’ll need it even in the high noon of Florida. 

Holosun HS510C red dot sight buttons, right-hand friendly.
The Buttons are responsive, but right handed friendly.

The optic has both a manual adjustment mode and an automatic mode. I prefer manual mode. The automatic mode doesn’t adjust to weapon lights in low light conditions, and a good weapon light will wash it out. 

Also, there is a very light tint—very slight. I’ve noticed various blue, amber, and purple hues among optics like the Meprolight Foresight, The Bushnell TRS 25, and SIG Romeo series. Compared to these optics, the Holosun provides a clearer picture overall. 

Durability

Shot after Shot 

Ammo is tight right now, so my testing requires me to be smart. I’m testing the HS510C and some various Scorpion magazines, so all of my shooting was through the Scorpion. It ate through 300 rounds of 9mm in total. A blowback operated gun creates more recoil than a 5.56 on average, so I think it’s a fair enough platform to use. Throughout this testing, the optic never flickered or failed like a light in a shady gas station.

Drop Testing

Next, I dropped it from shoulder height from several different angles. I dropped it a dozen times and tossed it back on the Scorpion. I used a little fingernail polish to mark the area so the zero would be as close to true as possible. The optic snapped back on, and I went at it again. The ding, ding, ding of my steel target informed me the optic held zero.

Holosun HS510C optic for rifles and shotguns.
The HS510C is a capable optic for rifles and shotguns.

I like my Scorpion a lot, so I didn’t want to drop it too many times, kind of like my first child. Still, like my first child, it needed to be dropped for durability testing to prove to me it was tough enough to last.

The weight of the gun makes it different from a stress standpoint. So I gave it three drops, one on each side and one from the top with the optic hitting first. I dusted off the gun, loaded a magazine, and went at it. Again, the optic held zero, and steel was rung. 

Holosun HS510C drop test.
The HS510C can seemingly take a good beating.

The Low-Cost Solution 

The HS510C is an excellent optic at a relatively low price. Holosun has produced a professional-grade optic at a hobbyist price point. If you are looking to make your lead delivery system more effective, efficient, and precise, then the HS510C is for you. 

Travis Pike is a former Marine Machine Gunner, a lifelong firearms enthusiast, and now a regular guy who likes to shoot, write, and find ways to combine the two. He holds an NRA certification as a Basic Pistol Instructor. is the world's Okayest firearm instructor, and a simplicisist when it comes to talking about himself in the 3rd person. Hit him up on Instagram, @travis.l.pike, with story ideas.

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