Holosun HS507COMP review: the window is the whole point

By the OpticVerdict Editorial Team.
Research-based review · Updated 2026-07-17

How we reviewed it: a research-based review built from the retailer specification sheet, the manufacturer's published figures and the verified owner-review record. We have not bench-tested this unit ourselves; the score is our editorial opinion and owner ratings are shown attributed to their source. See how we evaluate.

What it is

The HS507COMP is Holosun's competition-first open reflex sight: a 1x pistol optic on the RMR footprint, in a 7075-T6 aluminum housing, built around an oversized 1.1 x 0.87 in objective window and the Competition Reticle System. It weighs 1.7 oz, seals to IP67, is rated to 5000G of vibration, adjusts in 1 MOA clicks and runs on a single side-loading CR1632. The name is not decoration. Nearly every choice in it trades concealment and autonomy for speed on a stage.

Why the big window actually matters

A bigger window does not make a pistol more accurate. It makes the shooter faster, and it does so by widening the margin for a bad grip. Do the arithmetic on our own verified specs: 1.1 x 0.87 in works out to about 0.96 square inches of glass, against roughly 0.57 for the 507C's 0.63 x 0.91 in. American Rifleman puts that at about 67 percent more window. What that buys is forgiveness. A presentation that pushes the dot out of a standard 507C's window entirely will often still show it at the edge of this one, and a dot at the edge of the glass is a shot you can break now instead of a grip you have to fix first.

The same geometry helps between shots. Under recoil the dot climbs into the upper region of the window, which on a smaller optic is solid aluminum, so it simply vanishes and you wait for it to come back. American Rifleman's evaluator makes exactly this point: the tall glass keeps the dot in view through recovery, so you can be aggressive with follow-up shots. Owners say the same thing in plainer words.

“Bought this for my wife’s full size pdp that she uses for uspsa. The window is huge and the glass is clear. She didn’t have any issue finding the dot like she has in the past with the 507C. We love that one as well. It has too many reticles to mention. It’s awesome.”

Manny, verified owner (AZ), via OpticsPlanet

The CRS reticle, and why the 20 MOA ring is the one that matters

This is the second half of the "COMP" designation. The 507C runs Holosun's Multi-Reticle System: a 2 MOA dot, a 32 MOA circle, or both. The 507COMP runs the Competition Reticle System, which keeps the 2 MOA dot and the 32 MOA circle and adds intermediate 8 MOA and 20 MOA rings, giving eight selectable combinations of dot, ring, or ring-and-dot.

In practice one of those rings does most of the work. The 32 MOA circle is fast but visually loud, and a bare 2 MOA dot gets lost against a busy background during transitions. The 20 MOA ring lands between them: American Rifleman calls it the Goldilocks size, big enough to track boldly through slide reciprocation, tight enough to bracket an 8 inch steel plate cleanly at 15 to 20 yards. Owners who came from other Holosun reticle systems single out the same thing.

“This is my 4th Holosun optic purchase in 2 years... I have the MRS, and the ACSS Vulcan reticle units and this is my 1st CRS reticle unit. What’s really great about this one are the 8 & 20 MOA circle options. The 32 MOA circle on the others can be a bit too large and these smaller options; with or without the 2 MOA dot make for awesome target acquisition and the large window keeps you in the zone between shots and recoil.”

Prpunisher, verified owner (NJ), via OpticsPlanet

One honest quirk of the ring projection: there is an open gap at the 6 o'clock position of the 8, 20 and 32 MOA rings, a by-product of projecting concentric circles from one emitter. It is most obvious on the small 8 MOA ring, which reads as a horseshoe rather than a closed circle. Reviewers at Shooting Illustrated report it does not hurt speed or accuracy, but you should know it is there before it surprises you.

What Holosun gave up: the solar panel

Every other Holosun in this family, the 507C, the 407C, the 510C, carries a solar panel on the top strap. It does two jobs: it runs the dot if the battery is dead, and it adjusts brightness automatically as the light changes. The 507COMP has neither, because the enlarged window took the space the panel used to occupy. OpticsPlanet's feature list carries no solar entry, and SSUSA, the NRA's competitive shooting publication, reports the panel was removed to maximize glass.

So you manage brightness yourself with the two side buttons. Walk from a dim indoor bay into bright sun and the sight will not follow you; you break your grip and press a button. On a range or a match stage, where you know the light before you start, this is a shrug. On a defensive gun, where the whole point is that the sight handles conditions you did not plan for, it matters. Shake Awake still covers the on-off problem, sleeping the LED after 10 minutes of stillness and waking it on the slightest motion, and Holosun rates the CR1632 at up to 50,000 hours, though that figure is for the 2 MOA dot alone at setting 6. Run rings and it draws more; Holosun does not publish a figure for that, and neither will we.

The side battery tray is a bigger deal than it sounds

The CR1632 loads from a tray on the right side of the housing, so one screw gets you a fresh battery without dismounting the sight. Compare that with the Trijicon RMR, where the battery sits underneath: you pull the optic, swap the cell, re-torque the screws and then spend ammunition confirming zero again. Guns & Ammo makes this the practical case for the sight, and it is why competitors who swap batteries before every major match care about it more than anyone else.

What owners flag, plainly

A 5.0/5 average across 94 reviews leaves little to mine, and that in itself is worth saying: we found no pattern of failures, lost zero or dead electronics. The complaints that do exist are specific and come from people who like the sight. The most detailed owner review flags two: the lens sits close to the front edge of the housing, which is what buys the window size but also puts the glass more in the path of ejecting brass, and switching the reticle off means holding two small buttons at once.

“The lens is very close and not set back from the front edges of the frame which helps allows a larger viewing lens, but at the same time it is potentially easier to get hit by ejecting shell casings. After about 1,000 rounds - so far no damage to the lens. The other minor drawback is the fact that (as far as I know) I have to hold down 2 small buttons at the same time in order to turn the optic reticles off... of the 6 different red dot optics I own, the 507 Comp is by far my favorite.”

Rich, verified owner (MA), via OpticsPlanet

One more, from a competitor rather than a defect: if your pistol is already near a division weight limit, weigh it with the optic mounted before your next match.

“I zeroed this optic on Friday and competed with it on Saturday. I absolutely love it. Large window and crisp dot. I was able to pick up the dot extremely fast even during recoil... One thing to note...if your pistol is on the heavy-side, make sure that you weigh it with the optic to ensure you meet weight restrictions.”

mryoung74, verified owner (OK), via OpticsPlanet

Trade-offs, plainly

• No solar and no auto-brightness. You set the brightness by hand, every time the light changes. The 507C and 407C do it for you.
• Open emitter. Rain, mud, snow or pocket lint in the emitter well can bloom or kill the reticle. Fine on a range, a real liability on a duty or defensive gun.
• Too big for concealed carry. The 1.1 in window prints through light clothing and the squared housing can snag on the draw.
• Big glass is more exposed glass. One published hands-on test cracked the window in a two-foot drop onto concrete, though the sight held zero and kept working. A small armored optic would likely have shrugged it off.
• The 8, 20 and 32 MOA rings have an open gap at 6 o'clock, most visible on the 8 MOA ring.
• No mount or plate in the box, and OpticsPlanet states no warranty on this listing, so confirm coverage with Holosun before you buy on that basis.

Key specifications

Which one to order: OpticsPlanet lists this optic in two illumination colors on one page. The red HS507COMP is around $370 and the one we reviewed; the green HE507COMP-GR is around $400 , a 540 nm green emitter in an otherwise identical sight. Holosun's naming is consistent here: HS is the red model, HE the green. Several owners say they pick up green faster in any light, which is what the $30 between them buys. Separately, OpticsPlanet also lists Ronin editions of the 507COMP. Those are different products with a reduced reticle set, and we have not reviewed them.

On awards: this sight has no formal industry award, and we checked. There is no NRA Golden Bullseye, no NASGW Caliber Award and no Optic of the Year for the 507COMP, so we claim none. It is reviewed and recommended by American Rifleman, Guns & Ammo and Shooting Illustrated, which is editorial praise, not a trophy.

Should you buy it, and what else to consider

• Buy it for a competition or range pistol, or a pistol-caliber carbine, where the window and the CRS rings buy real speed and the missing solar panel costs you nothing.
• Buy the 507C instead if this is a general-purpose or carry gun: smaller window, but Solar Failsafe, auto-brightness and far less to print or snag. See 407C vs 507C.
• Step down to the plain 2 MOA HS407C-X2 (around $190) if you will never touch a reticle menu.
• Mounting a Glock MOS? The plate question decides as much as the sight does, and the SCS MOS skips the plate entirely. See best red dot for a Glock.
• Want this window on a rifle or shotgun? The HS510C (around $310) gives a 32x24mm window, a 65 MOA circle and keeps the solar panel.

FAQ

More: best red dot sights · best pistol red dots · 407C vs 507C · Holosun HS407C-X2 review · Holosun HS510C review.