Aimpoint ACRO S-2: The Shotgun Sight Reinvented

When reflecting on the last few decades, I have to give due reverence to the firearm industry’s progress and innovation. I could highlight quite a few advancements, but electronic sights stand apart for many reasons. At one time, iron sights were standard accouterment for handguns and rifles; now, irons take a back seat to magnified optic and red dot mounting capability.

Despite many purpose-built rifle and handgun red dot sights, ghost ring, notch-and-post, and rib-and-bead sights remain standard for shotguns. In most instances, a red dot on a shotgun meant adapting a rifle or pistol red dot to scattergun applications. However, the new Aimpoint ACRO S-2 introduces us to a dedicated shotgun red dot sight unlike any before it. Here’s why the ACRO S-2 marks the beginning of a new generation of dedicated shotgun red dot sights.

The Aimpoint ACRO Series

After half a century, Aimpoint requires little to no introduction. Aimpoint introduced the first true red dot sight, the “Electronic,” in 1974. Since then, Aimpoint continued to advance red dot technology and remains a leader in their field. Personally, I’ve employed several Aimpoint models in a professional role for well over a decade. Most recently, the Aimpoint ACRO P-2 made its way onto my duty handgun as the latest addition. Introduced in 2021, the P-2 is the ACRO line’s next generation of fully enclosed emitter handgun red dot sights. While its perceived size led to the nickname “the mailbox,” the ACRO’s weight (2.2 ounces) shows it’s anything but bulky or heavy.

Furthermore, the ACRO’s proprietary mounting design eliminated a common failure point amongst many other handgun optic mounting designs. With only a couple of months on the ACRO P-2, it’s hard to justify why I didn’t go to the mailbox sooner.

While the ACRO P-2 is certainly adaptable to shotgun use, it encounters many of the same inherent issues accompanying the use of handgun and rifle red dot sights on a shotgun. For example, most red dot sights require a rail adapter, mounting plate, or some other hardware for compatibility. In those cases, the sight sits awkwardly high above the bore axis.

While doable on a fighting shotgun, most shotgun stocks are designed to place the shooter’s head in line with the top of the receiver, rib, and front bead. With an elevated red dot, the shooter’s head lifts off the stock, causing an inconsistent sight picture. In short, you want the optic mounted in line with the sights or as low as possible. From this need, the Aimpoint ACRO S-2 appeared as a first-of-its-kind dedicated shotgun red dot sight.

ACRO S-2 Mounting System

The Aimpoint ACRO S-2 features a completely redesigned mounting system from previous ACRO models. While the original ACRO’s mounting system was geared towards attachment to a pistol, the ACRO S-2 attaches to the shotgun rib. According to Aimpoint’s literature, the “height of optical axis” is 15mm “measured from top of mechanical surface.” In plain language, it’s 0.6 inches from the center of the sighting window to the top of the shotgun rib. After nearly two decades of testing and training with different iron, magnified, and red dot sights across various firearms, the ACRO S-2 is undoubtedly the easiest transition I’ve ever made to a new sight setup. If seeking a one-word description, “intuitive” immediately comes to mind.

The ACRO S-2 includes an eight-piece set of carbon fiber support and locking base plates in varying dimensions. An included guide determines which plate or support works depending on the shotgun rib’s dimensions. The ACRO S-2 mounting system is compatible with shotgun rib thicknesses of 1.3 to 3.6 mm and widths from 6 to 12mm. These dimensions make the S-2 compatible with many common shotgun ribs, including some broad trap ribs. Aimpoint recommends using a set of calipers to accurately measure your shotgun’s rib width and thickness to determine proper fit and compatibility.

For the majority of testing, the ACRO S-2 remained on a Mossberg 930 JM Pro Series Tactical Class. On an important note, Aimpoint recommends checking the mounting screw tightness after an initial firing session. Why do that?

After 100 rounds of 12-gauge bird shot, the sight drifted noticeably forward on the rib. After a small adjustment and quick tightening of the screw, it’s held in place ever since. Shotgun recoil is unforgiving, and, like any gear, I strongly recommend checking the mounting screw to ensure it hasn’t changed torque between firing sessions.

Shooting with the ACRO S-2

While the ACRO S-2 didn’t attend any bird hunts, it received a treatment of clays and steel target work. The reticle’s low profile produced a consistent and easy-to-find sight picture across several shotgun setups. With some red dots, the reticle easily drifts out of view. For the ACRO S-2, losing the reticle became a challenge. After handing the shotgun and optic combination off to several shooters of varying skill levels, I received universal positive feedback on the S-2’s intuitive and natural aiming presentation and profile. Unlike many aftermarket red dot sights, the ACRO S-2 feels like a natural extension of — and improvement over — traditional rib-and-bead sighting systems.

The ACRO S-2 features more than a new mounting system, which makes it compatible with ribbed shotguns. To make the S-2 more applicable to shotgun work, Aimpoint increased the reticle size from 3.5 to 9 MOA. While the smaller MOA reticle works well with precision handgun work, shotguns embrace forgiveness with large shot patterns. The 9 MOA dot provides some room for error when shooting aerial targets without obscuring the sighting window or target.

Traditionally, the ACRO series included 10 brightness settings with several night vision-compatible levels. Some folks may approach shooting clays or upland birds differently, but I haven’t found a market for hunting doves with night vision. Accordingly, the S-2 foregoes the night vision settings in favor of ten increased brightness levels. With increased brightness, the reticle is less likely to wash out against a bright sky or background. While seemingly common sense, this change overcomes a longstanding problem with adapting micro pistol red dots onto shotguns.

Even at its highest setting, the S-2’s reticle remained crisp, clear, and visible against bright backgrounds. Of course, the S-2 retains Aimpoint’s reputation for extremely long battery life. While environmental conditions and brightness settings factor into performance, experience tells me to expect a year or more of reliable use out of a single CR2032 battery.

The Aimpoint ACRO S-2 and the Future of Shotgun Red Dots

I’ve always been an admittedly strong proponent of Aimpoint’s products. After years behind rifles outfitted with a T-1 or PRO, Aimpoint proved their durability and effectiveness enough for me to recently acquire an ACRO P-2. With the ACRO S-2, Aimpoint rounded out their collection of purpose-built red dot sights with a fantastic addition.

While early in the game, I think the S-2 could change the conversation surrounding the practicality of red dots on shotguns. The ACRO S-2 is currently offered on GunMag Warehouse for $755.99. If you’re looking for a red dot sight designed for sporting, recreation, competition, or even tactical shotgun applications, the S-2 is money well spent.