The Holosun HS510C in Flat Dark Earth is a 1x open reflex sight with a green Multi-Reticle System — a 2 MOA dot, a 65 MOA circle or both — behind a 0.91 × 1.26 in window, on an integrated quick-detach Picatinny mount.
The rimless window is the reason this sight sells: there is no tube edge to look past, so the shooter keeps both eyes open and the 65 MOA circle drops onto a close target almost without conscious aiming.
A titanium hood shields the emitter over an aluminium body finished in Flat Dark Earth by MAO, rated IP67, tested to 1000G and usable from −30 °C to 60 °C. It measures 3.30 × 1.68 × 1.78 in and weighs 4.94 oz. The 540 nm green LED runs 12 brightness settings — 10 daylight and 2 for night vision — in manual or automatic mode with a lockout, adjusting 0.5 MOA per click across ±50 MOA, and the side-loading CR2032 gives up to 50,000 hours at setting 6 with Solar Failsafe and Shake Awake behind it.
Practical shotgun, 3-Gun and carbine shooters buy it for the circle and the quick-detach mount; the green reticle holds up well against dark ground at dusk. Be clear that the emitter is open rather than enclosed, so heavy rain or mud on the front glass will affect the reticle in a way a sealed sight would not, and it needs a Picatinny rail section rather than a bare receiver.
Why shooters choose the HS510C
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Reticle — green Multi-Reticle System — 2 MOA dot, 65 MOA circle or circle-dot
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Window — 0.91 × 1.26 in, rimless, with a titanium protective hood
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Illumination — 12 settings — 10 daylight and 2 for night vision, manual or automatic
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Power — side-loading CR2032 with Solar Failsafe and Shake Awake, up to 50,000 hours
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Mount — integrated quick-detach Picatinny mount
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Housing — aluminium with MAO Flat Dark Earth finish, IP67, 1000G
What the HS510C fits
The integrated mount clamps to any Picatinny rail, which on a shotgun means a rail section on the receiver or rib. The same sight with a red reticle in the same finish is the HS510C red in FDE, in black it is the HS510C red, and the magnifier pairing is the HS510C and HM3X combo.
Specifications
| Type |
Open reflex sight, 1x |
| Reticle |
Multi-Reticle System — 2 MOA green dot / 65 MOA circle / circle-dot |
| Light Source |
540 nm green LED |
| Window |
0.91 × 1.26 in (23 × 32 mm) |
| Illumination |
12 settings — 10 daylight / 2 night vision, manual and automatic |
| Adjustment |
0.5 MOA per click, ±50 MOA |
| Battery |
CR2032 side-loading, up to 50,000 hours at setting 6, Solar Failsafe |
| Mount |
Integrated quick-detach Picatinny |
| Housing |
Aluminium with titanium hood, MAO Flat Dark Earth, IP67, 1000G |
| Operating Range |
−30 °C to 60 °C |
| Dimensions |
3.30 × 1.68 × 1.78 in |
| Weight |
4.94 oz (140 g) |
| MPN |
HS510C-GR-FDE |
A wide green window on a lever mount, in a finish that matches the furniture. Order the HS510C today — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: Green Dot Sights, HS515CM or browse all Holosun.
