The Aimpoint ACRO - Purchase & Installation

During the SHOT show in 2019, Aimpoint released a new contender for the pistol mounted red dot sight market called the ACRO. Aimpoint has become the default option for red dot sights on long guns of all stripes due to a history of producing optics that have extraordinary battery life and a well earned reputation for nearly bomb-proof reliability.

Red dots are nothing new to handguns, of course, as competitors have been using them for years. Crucially, they have been running red dots on a static mount that is attached to the frame of the handgun. This means the optic doesn’t really experience any of the forces involved in the cycling of the pistol. Unfortunately this arrangement isn’t practical for a duty or concealed carry weapon.

It became clear fairly early on that if you want to have a red dot sight (RDS) mounted to a pistol for duty or concealed carry that it needed to be fitted to the slide of the pistol somehow. Various attempts were made at fixtures that fit into the rear sight dovetail allowing mounting an optic. Eventually it seemed that milling the slide to accept the optic directly is the best way to accomplish the task.

The forces an optic is exposed to while mounted to the slide of a semi-automatic handgun are considerable, especially when you consider how small the internal components have to be to create an optic that is compact enough to fit up there in the first place. Trijicon’s popular RMR sight was a natural fit for the purpose, but early generations of the RMR tended to get beaten to a premature death living on top of the slide of a pistol. Later generation RMR’s are much improved in durability, but their open-emitter design and the need to remove the optic to replace the battery (often requiring re-zeroing your pistol) left plenty of room for an RDS option that was more impervious to the elements and allowed a battery change without removing the optic.

Enter the ACRO: A closed emitter design that incorporates what Aimpoint has learned about making a durable, reliable optic in the last 45 years. Their long-gun oriented red dots are the gold standard for durable, combat-reliable optics with widespread adoption by police and military forces around the world. So naturally if anyone could make the killer pistol RDS it would have to be Aimpoint, right?

Aimpoint even claims that the optic was tested to 20,000 rounds through a Glock chambered in .40 S&W. That exact weapon is used by an elite counter-terrorism unit that has been experimenting with combat application for pistol-mounted red dots for years. To those in the know, this was no coincidence.

I pre-ordered my Aimpoint shortly after SHOT and in late May I received my ACRO from the big brown truck of happiness.

Decisions, decisions…

There are some decisions to be made after you have started walking the path of the pistol-mounted RDS.

The first thing you must decide is how, exactly, are you going to mount the optic? Are you going to have a company mill the slide of your pistol? Perhaps purchase a new slide that comes pre-milled for your optic of choice?

I made the decision to purchase a Gen5 Glock 17 MOS pistol. I knew that Aimpoint had done a lot of testing with Glock MOS pistols and that the 9mm MOS offerings from Glock were likely to win a number of large federal contracts in the near future. Shortly after my purchase the US Border Patrol and the United States Secret Service both announced they were adopting Gen5 9mm pistols for issue, and that MOS guns were going to be part of those contracts.

Purchasing the MOS Glock avoids the need to have a pistol permanently altered at considerable expense, and keeps my equipment in line with the way large-scale institutional users will likely end up mounting dots to their pistols. Plus it was an excuse to buy a new gun…and who doesn’t like that?

If you choose to have a slide milled to accept the optic, you have to choose the company doing the work with care: Not all milling jobs are created equal. Work from a reliable shop who knows exactly what they are doing might be a little more expensive, but given the problems I’ve seen from bad mill-jobs out there I’ll happily pay a few percentage points more to get a product that isn’t a perpetual headache.

May I take your plate, sir?

If you buy a factory MOS style gun, they are not cut for a specific optic. This means you will need some form of adapter plate for the optic. Again, because I knew how much work Aimpoint had done with Glock MOS pistols I trusted that they would have an adapter plate that wouldn’t give me heartburn.

Aimpoint has a number of different adapter plates available to fit the ACRO to various factory optics-ready options, so you aren’t necessarily stuck buying a Glock if you want to use the ACRO.

I used the factory mounting screws included with the Glock MOS pistol (the Glock MOS guns come with a couple of plates) to mount the Aimpoint plate to the slide of the pistol. The ACRO mounting plate comes with a small vial of Vibra-Tite. Our friends at Aridus Industries have found that the Vibra-Tite product works a bit better to prevent the loosening of screws than the typical LocTite products, so I was happy to see I didn’t need to break out the tube of Vibra-Tite I keep around. Following the instructions for mounting the plate and using the Vibra-Tite very carefully is important if you want to avoid having the plate come loose on you down the road.

Iron Sights

Yes, even though I purchased an optic whose raison d'être is to be the un-killable pistol-mounted RDS, I was going to make absolutely certain that I had good iron sights on the gun. I was specifically looking for sights that would give me a lower 1/3 co-witness, meaning the sights are visible through the lowest third of the optic’s window.

Wayne Dobbs (who does some work for Aimpoint) mentioned that they had mounted Ameriglo suppressor-height sights on their test Glock MOS guns and that they provided a good lower 1/3 co-witness. I ordered the Ameriglo GL-511 sights (tritium front sight with an orange outline, plain black rear sight) to function as the backup iron sights on the pistol.

The sights do indeed co-witness in the lower 1/3 for a sight picture that isn’t what I’m used to, but is still more than usable, even at speed. Spoiler alert: This would come in handy later.

Installation

Installing everything was fairly easy. I would urge you to follow the instructions for installation carefully. Take the time to degrease the screws and the holes they will screw into. Follow the Vibra-Tite instructions for use to the letter. Don’t go nuts over-torquing the screws. Etc.

I would recommend installing your iron sights and getting them set up more or less for mechanical zero before you start mounting the optic. It’s simply easier to work with the slide to mount the sights properly without the optic in the way.

The entire process took roughly half an hour, but primarily because I took the time to thoroughly degrease the parts and I allowed for the manufacturer recommended setup time for the Vibra-Tite. While the process is not difficult it is detailed, so take your time and get the details right. Ideally you expect the resulting setup to survive thousands of rounds of live fire and manipulations…so it’s worth your time and effort to try and get it right.

All that was left was to head to the range to zero the irons and the ACRO…and we’ll discuss that next time!