AR-15 Mounting Options for the Aimpoint ACRO Red Dot Sight

Red dot sights have taken over the optics world for good reason. They are durable, simple, effective, and have evolved so much that there are a couple of red dot categories: full­size and mini.

Mini red dot sights (MRDS) continue to find their way into areas previously unimaginable. When the MRDS first arrived on scene nearly 20 years ago, some saw its immediate application on a pistol’s slide. Small enough to ride on top without adding any width to a pistol, such examples were also light enough that they didn’t negatively affect the slide’s operation, generally.

Placing a small illuminated dot on a target also made accurate shooting much easier (as competition shooters already knew), but especially so for those with aging eyes. An MRDS doesn’t require the eye to focus on the front sight. The shooter just has to look through the optic and focus on the target. My tightest groups with a pistol have come from ones equipped with red dot sights.

Traditional MRDS optics never gained much traction on rifles because almost all of these sights use an open emitter. Having an “open emitter” means that the sight’s light source is exposed to the elements as it projects the beam of light onto the optic’s lens. Many of the small “L” shaped red dot sights on the market today are of the open-emitter design. Anything that drops onto these MRDS can block the emitter, eliminating the dot on the lens and effectively rendering the optic useless. However, there is one MRDS that has a closed emitter, and it makes a ton of sense as a lightweight rifle optic: the Aimpoint ACRO.

While there are many red dot sights available, none have Aimpoint’s heritage and performance record. I was issued an Aimpoint CompM2 when I reported to the 82nd Airborne Division in December 1999. I later carried one in Afghanistan and Iraq with 3rd Special Forces Group. I never once, through four combat deployments, saw any of my unit’s issued Aimpoint optics malfunction.

This left an impression on me because combat is hard on equipment. Running men sometimes fall down and land on their rifles. Rifles are also used to physically strike things, and sometimes the optic bears the brunt of the blows. The simple act of getting into and out of vehicles and aircraft often leads to equipment getting bumped and dumped, with little thought given to protecting a rifle’s optic.

Regardless of the abuse it takes, it’s important for any optic to maintain its shape. As soon as the housing on a sight deforms, it’s likely the glass lens(es) will break, or the electronics will become damaged. One of Aimpoint’s durability secrets is their use of 7075 aluminum on all of its Comp-­series housings. This type of aluminum is a tough material to machine, but it resists deformation when struck, which means that the glass lenses of the red dot sight and the electronics inside are protected.

Most of the closed-­emitter red dot sights today are larger than the Aimpoint ACRO. I have purchased a couple of T-­1 and T-­2 red dot sights simply based on what I saw while serving in the military, and I like them very much. Those sights are slightly larger than the ACRO and have 6061 aluminum housing. I’ve never seen 6061 fail, but in a worst-­case scenario I’d prefer to have the more durable 7075 housing because I saw the 7075 get beat up pretty good with no functionality issues. Hence, military requirements almost demand this feature. If a someone wants the smallest closed-­emitter red dot sight available that’s also as durable as anything the military uses, the Aimpoint ACRO is the only game in town.

While the ACRO predominantly sees use mounted on pistols, it is also an excellent option for duty as an AR-15’s primary red dot sight. It makes an especially compelling selection when paired with today’s popular AR pistols that are equipped with arm braces. The AR pistol with an arm brace represents the most usable ballistic horsepower in as small a package as possible.

---

There are currently two AR-­15 pistol mounting options available when using an ACRO as a primary optic. The first is Aimpoint’s quick-detach (QD) mount, which is also the only QD mount currently available for the ACRO. The QD mount puts the optic 39mm above the rail, making it a lower 1⁄3 co-­witness mount. (The lower 1⁄3 co-­witness just means that the iron sights on the AR pistol will be visible in the lower third of the ACRO’s window.) Should the battery die or the optic become inoperable, the shooter can immediately switch to the iron sights still visible through the ACRO. It’s a degree of redundancy that’s usually a good idea.

The ACRO attaches to the top of the mount with the integral screw built into the optic’s housing. There are a series of lugs at the bottom of the ACRO housing that mate with recesses cut into the Aimpoint mount. They prevent the optic from shifting under the heaviest recoil. Aimpoint’s mount attaches to both Weaver and Picatinny rails, and has a spring-­loaded locking device that ensures the QD arms never unintentionally unlock. The locking arm and mounting hardware are made of steel, and the body of the mount is machined from aluminum.

If you want the most durable mount for the ACRO, this second option is where I would look first.

Reptilia (reptiliacorp.com) is run by the same handful of career ­firearms-industry professionals that started this small company in order to fill the needs of the Special Operations and intelligence communities. They make premium products for use under the most difficult circumstances. This is also one of those rare times a premium product won’t cost a lot of money. The mount Reptilia offers for the ACRO sits at the 39mm height for the lower-third co-­witness and retails for $95. It is machined out of 7075 aluminum and has nitride steel mounting hardware that provides excellent corrosion, fatigue and wear resistance, especially when compared to untreated steel.

While the regular red dot sight will probably remain more popular on an AR-­15 than the ACRO, my AR-­15 travel companion currently wears an ACRO on a Reptilia mount. It’s a small, yet ­potent package that represents the best that modern manufacturing offers. The ACRO is durability and reliability in compact a package.

Aimpoint ACRO P-1 Specs

• Power: 1X
• Objective: 44mm
• Size: 1.9 in. (L) x 1.2 in. (W) x 1.2 in. (H)
• Window: .63 in. x .63 in.
• Battery: CR 1225
• Reticle: 3.5 MOA dot
• Weight: 2.1 oz.
• Eye Relief: Unlimited
• MSRP: $599
• Manfacturer: Aimpoint, 877-­246-­7646, aimpoint.us