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Aimpoint Acro vs Holosun 509T Sealed MRDS

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At the risk of repeating ourselves ad nauseum, it’s clear that red-dot sights on handguns will become as common as optics on rifles. They’re fast and precise. With a red-dot sight, simply superimpose the dot on your target and press the trigger — no need to line up the front sight, rear sight, and target; no need to shift your focus around; no need to bemoan your inability to even see your sights at all as you get older. 

These days, most micro red-dot sights (MRDS) are open reflex sights, like the popular Trijicon RMR, with an emitter that projects the dot on a glass lens. This results in a compact, functional sight. However, on a sight like the RMR, that emitter, while protectively tucked into rear housing, is still exposed. Jam your pinky into the open area behind your RMR’s lens to see how you can block the emitter. It’s not common, but debris, condensation, and moisture can cause this to happen.

If you’re worried about this, the solution is to completely enclose the emitter, shielding it from the elements at the expense of additional bulk. Aimpoint, renowned for its nearly indestructible, combat-tested sights, was the first out of the gate in 2019 with the Aimpoint Acro P-1, specifically designed for pistols and other applications calling for a small, sealed red dot. Upstart Holosun has been churning out winners of late with their excellent 507 and 508 sights, unveiling at the beginning of 2020 the enclosed 509, which started trickling out to consumers in late 2020.

aimpoint acro mounting base
Both sights feature proprietary mounts with a recoil lug and are clamped down from the side.


Let’s discuss how the Aimpoint Acro P-1 and 509T stack up:

>> Construction and design: Both sights are rectangular and boxy, like a mailbox, with a protective rear lens and a front lens on which the reticle is projected; the Aimpoint Acro P-1 has an additional protective window in front. The Aimpoint’s housing is aluminum, while the Holosun is titanium. The Holosun 509T is essentially a regular MRDS with the housing extended rearward to seal off the whole system; most of the working bits are at the bottom of the sight with a wide optical window sitting on top of it, pushed out to the edges. The Aimpoint Acro P-1 is more of a square, concentric design, with a smaller square optical window in the center surrounded by a thick housing, with the mount and emitter on the bottom, the battery on one side, and controls on the other. This also extends the Acro’s window lower and closer to the bore than most other sights. The Acro is bulkier than the Holosun 509T; it’s just a hair taller and wider, but almost half an inch longer.

>> Mount: Sights like the RMR are mounted using screws that thread in from above, not possible with these sealed sights. Both have a recoil lug that fits in a slot and are clamped down from the side. Each is proprietary; a variety of adapter plates are available for both to fit RMR-pattern cuts, the Glock MOS system, and others. For the most secure install and to sink your sight as low as possible, gunsmiths can mill your slide to directly attach your Aimpoint Acro P-1 or Holosun 509T.

>> Glass and tint: Both sights have clear glass with some distortion at the edges; it’s very slight in the Aimpoint and more noticeable in the Holosun. The Aimpoint Acro P-1 appears spot on at 1x; the 509T is a touch over-magnified. Both have minimal vertical or horizontal displacement. A bluish tint is common in red-dot sights, due to coatings that make the reflected red dot look brighter while using less power. The Holosun 509T has a noticeable blue tint throughout the entire window; the Aimpoint Acro P-1 appears as a gradient — more blue on top and less on the bottom. Among our selection of sights, the Acro has the least tint, followed by the 507C, the 509T, and finally the RMR, which is noticeably darker.

aimpoint acro vs holosun 509t
The Holosun on the left is mounted on CMC Triggers’ new KRAGOS slide with an RMR cut, using an adapter plate. The Aimpoint on the right is attached using the Glock MOS system with an Acro-compatible plate.

>> Reticle: The Aimpoint Acro P-1 has a 3.5 MOA dot, a bit large for some while appreciated by others in a pistol optic. Trijicon offers RMR variants with different-sized dots; it’d be nice if Aimpoint did the same to suit your preference. The Holosun 509T features a more precise 2 MOA dot, plus a 32 MOA circle that you can enable for an EOTech-like reticle. The circle-dot configuration is handy as a large reticle for mindless hosing up close or even as a reference for hold-overs at distance or range estimation. Most of the time, we prefer just the center dot. You set elevation and windage on the Aimpoint with a T-10 Torx driver, at 0.6 MOA per annoyingly mushy click. The Holosun has much more positive detents, at 1 MOA per click. However, they’re irritating if you don’t have Holosun’s easily misplaced tool or a jeweler’s screwdriver at hand, as the slots are small and shallow.

>> Brightness: Brightness is in the eye of the beholder; a searing bright dot to one may be middling to another. In either case, especially for a pistol optic, a bright dot is important. You need to be able to pick it up at high noon or while irradiating a threat with your 1,000-lumen light. To our eyes, both sights had similar brightness at their highest settings — plenty bright, though not quite as bright as an RMR06 and roughly equivalent to level 11 on an Aimpoint T-1. Both reticles were round and crisp to our testers with good vision and smeared or distorted to those with visual problems like astigmatism.

>> Battery life: There was a huge kerfuffle when the Aimpoint Acro P-1 first arrived, as end users discovered battery life nowhere near their expectations. People were accustomed to Aimpoint sights lasting forever, and it didn’t help that Aimpoint’s marketing cited 1.5 years of battery life … at setting 6, which is barely visible. At setting 7, Aimpoint says it should last over six months. One of our team carried an Acro for half a year, leaving it on all the time, usually at position 8. He had to replace the battery every other month.

Let’s dig deeper and examine the batteries that these sights use. The RMR is known for its excellent battery life; it uses CR2032 cells, typically rated for 220 mAh of capacity. However, 2032s are 0.8 inch in diameter and sit on the underside of the RMR. The Holosun uses a smaller CR1632 in a battery tray so they can be changed without uninstalling the sight and affecting zero. They’re rated for 140 mAh. Meanwhile, the Aimpoint Acro P-1 gobbles up tiny CR1225 batteries, rated for a paltry 50 mAh. It shouldn’t be surprising that such a small battery reduces battery life. Holosun claims over five and a half years at a similarly dim setting 6. With almost three times more battery capacity, this makes sense. But if that weren’t enough, Holosun fitted solar panels that can power full brightness in the sun even with an empty battery tray. Moreover, it has a “shake awake” feature, putting the sight to sleep to conserve power when motionless and turning back on when it’s moved.

aimpoint acro vs holosun 509t
The Acro P-1 uses tiny CR1225 batteries, which have little more than a third the capacity of the 509T’s CR1632 batteries and less than fourth of the RMR’s CR2032 cells.

In product design, everything’s a trade-off — Aimpoint could’ve packaged the Acro to accommodate a larger battery, but this would’ve required compromises in other areas. The lighter tint on the Aimpoint Acro P-1 increases power consumption as well. Bottom line, if you want the attributes offered by the Acro, be prepared to replace batteries on a schedule or don’t leave it on all the time.

>> Controls and features: Aimpoint typically takes a KISS approach to its products, perhaps thinking of the type of folks who enjoy snacking on crayons. The Aimpoint Acro P-1 has no additional features beyond adjusting brightness and powering on and off. It has two large rubber buttons on the side; they’re easy to use and feel very nice. They’re recessed to prevent inadvertent activation, but if you manhandle your Acro like a charging handle, it’s possible to accidentally hit one of the buttons and change your brightness setting.

In contrast, Holosun has packed the Holosun 509T full of features. We already talked about the reticle, shake awake, and solar panels. You can also configure the sleep timer to 10 minutes, 1 hour, 12 hours, or never. You can manually set the brightness or select an auto mode that automatically adjusts based on ambient light. The 509T has two medium-sized buttons on the side with positive tactile feedback and a lockout mode that deactivates them.

>> Ruggedness: The Holosun is durable and rugged, but the Aimpoint ratchets it up further. While the Holosun can be submerged to 1 meter, you can dive down to 25 meters with an Acro. The Holosun 509T is rated to work in minus 22 to 140 degrees F, the Aimpoint Acro P-1 for minus 49 to 160 degrees. The Holosun has a side-loading battery tray secured by a small screw; the Aimpoint has a hefty battery cap that threads into the side of the housing.


We mounted the Aimpoint Acro P-1 and Holosun 509T on MOS Glocks and had a few shooters of varying skill levels try them out and shoot some timed drills. Both sights worked well and without incident. Some felt the smaller and lighter Holosun provided a little better balance in the hand, but it didn’t really affect performance. Between the two, our testers gravitated to the Holosun, preferring its handling and features.

The most inexperienced shooter didn’t have much time behind pistols with red dots. While subjectively he didn’t like the thick housing on the Acro, he felt it was actually a little easier to find the dot with it when presenting the gun. His timed drills were too inconsistent to draw quantitative conclusions between the sights. Our other shooters were more experienced and posted similar times with either sight. The timer doesn’t play favorites, so we called it a draw at the range.


Do you really need an enclosed emitter? For concealed carry, a regular MRDS is just fine. But if you want that extra durability, we didn’t have difficulty concealing these slightly heftier sights. If your pistol is more exposed, such as a duty weapon, a sealed red dot could provide welcome additional insurance against that bastard Murphy. They’re also nice choices for compact weapon systems or guns with low sight planes like shotguns.

With equivalent performance on the clock at the range, deciding whether the Aimpoint or Holosun is best for you falls to other factors.

holosun 509T-RD

Aimpoint made specific design decisions resulting in a bulkier sight, smaller window, minimal features, and significantly shorter battery life. Aimpoint has a hard-earned reputation for simple, bombproof sights, and they clearly wanted that to extend to the Acro. If you expect to find yourself 25 meters underwater with your sidearm, the Acro’s definitely for you. If you fit that description, you might also be in the type of unit that has a limitless supply of batteries to swap out for every mission. However, the short battery life and oddball CR1225s make it hard to recommend the Aimpoint Acro P-1 for SHTF. But if you want the Acro and its unique qualities for concealed carry or duty use, no need to get in internet arguments — buy batteries in bulk, schedule reminders on your phone to replace them (e.g. the first of every month), and drive on.

The Holosun 509T offers more features — all of them useful, from the solar panels to selectable, auto-adjusting reticles to shake awake to lockout mode — and much better battery life, at a lower price. Overall, the Holosun is a great sight that’s only slightly larger than a standard MRDS. What’s not to like? For most people, we suggest you look to the 509T first. 

aimpoint acro vs holosun 509t

Aimpoint Acro P-1

Reticle: 3.5 MOA Dot
Adjustments: 0.6 MOA Per Click
Brightness Settings: 6 daylight, 4 night vision
Window Size: 0.63 by 0.63 inch
Dimensions: 1.9 by 1.2 by 1.2 inches
Weight: 2.1 ounces
Housing: Aluminum
Submersion Rating: 25 meters
Working Temperature Range: Minus 49 to 160 degrees F
Battery Type: CR1225
Battery Life: 1.5+ years at setting 6; 6+ months at setting 7
MSRP: $599

Holosun HE509T-RD

Reticle: 2 MOA dot, 32 MOA circle
Adjustments: 1 MOA per click
Brightness Settings: 10 daylight, 2 night vision
Window Size: 0.66 by 0.9 inch
Dimensions: 1.6 by 1.16 by 1.13 inches
Weight: 1.7 ounces
Housing: Titanium
Submersion Rating: 1 meter
Working Temperature Range: Minus 22 to 140 degrees F
Battery Type: CR1632
Battery Life: Up to 5.7 years at setting 6
MSRP: $506

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