The Intermediate Range Rifle & Optics

Take a trip back in time with me to North Hollywood, CA on February 28, 1997.

It’s a pretty normal morning at the Bank of America until 9:17 AM when two heavily armed robbers bust into the bank to rob it.

The two bank robbers expected that they would have eight minutes before police would respond to the alarm tripped in the bank. They didn’t realize that before they’d even begun the robbery they had been spotted by an LAPD unit manned by officers Loren Farrell and Martin Perello. The officers called in the bank robbery and LAPD responded in force.

When the two robbers walked out of the bank they found themselves confronted by several LAPD officers who had taken up strategic positions waiting on their exit. The robbers immediately opened fire and the police responded in kind. In the almost hour long firefight that resulted, the robbers fired more than 2,000 rounds of ammunition and police fired more than 650 rounds from their issued weapons without much effect on the violent criminals.

When I saw news coverage of the North Hollywood Shootout as it was happening I remember thinking that a couple of officers (or even hunters) armed with a scoped .30-30 or .30-06 deer rifle could have completely altered the course of that fight.

Within the United States the need to defend yourself against a violent assault tends to happen at ranges we can measure in feet. Even so, there are plenty of occasions where police especially are confronted by the need to deal with a threat at extended distances. How do you arm an officer with a weapon that works at close range but will also allow them to reach out to beyond 100 yards with precision in an incident like the North Hollywood Shootout?

In Iraq, Afghanistan, and other “interesting” locations on the globe our military forces have found themselves needing to answer the same question. Combat units engaged in close range fights inside of structures and then immediately had to engage the enemy entrenched in distant buildings firing on the building they were still in the process of clearing. Unlike violent criminals or the terrorist forces our troops have fought for the last couple of decades, our police and military forces have to be concerned with positive identification of a threat and accountability for where their bullets go in the use of lethal force.

The concept of a low power variable optic mounted on a rifle chambered in an intermediate cartridge is not new. If you look at pictures from the Vietnam war you will have no trouble finding evidence of the then-new M16 rifle with various optics mounted to the carry handle.

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The magnification in these optics was usually 3x or 4x (although you can find some deer hunting scopes mounted to them as well) and helped make positive identification of a threat while allowing more precise engagement out to the realistically effective range of the rifle. These virtues came at the cost of speed and ease of use at closer range. Using techniques like the Bindon Aiming Concept it was possible to compensate for those drawbacks and still use the optic effectively at closer range.

In the late 1980’s Trijicon introduced the ACOG, an incredibly durable 4x scope that would see fairly wide spread adoption by segments of the Army and by the USMC. An improvement over the older Colt scopes, it was still a fixed 4x scope which made use at closer ranges more difficult.

At this point the red dot optic was becoming king of the hill for close range engagements. Some clever people thought that what really needed to exist was an optic that combined the best features of the red dot optic with the abilities of a magnified optic to help in positive identification and precision engagement.

That led to the development of the S&B Short Dot, a 1.1x-4x optic with an illuminated dot reticle. The 1.1x setting allowed a fast, nearly distortion free view through the optic similar to what you can get through a quality red dot while also allowing the magnification to be cranked up for longer range tasks. The optic was heavy and incredibly expensive, but very effective.

Over the last ten or so years the concept of an illuminated reticle, variable power optic with a 1x (essentially no magnification) setting that allows speed at close range along with identification and precision at longer ranges has found form in a wide variety of options on the market. Today practically every optics manufacturer makes at least a couple of what we call low power variable optics.

You might wonder, then, why they have not made the traditional red dot optic completely obsolete. (And, yes, I am old enough to find using the term “traditional” in concert with a red dot optic incredibly amusing!)

The LVPO optics tend to be more fragile than the rugged Aimpoint or fixed power ACOG optics. They tend to consume batteries more quickly than the Aimpoint optics, requiring keeping up with your maintenance to keep the illuminated reticle working for you. The optics themselves and the mounts necessary to use them tend to be heavier. Most importantly, a duty quality LVPO is considerably more expensive than a traditional duty grade red dot optic.

Consider the Vortex Viper PST-II optic on my personal rifle. Even factoring in street price for the optic and a decent mounting solution you are still looking at a minimum of $700-$750 on top of the cost of the rifle itself. The Vortex Viper PST-II is probably the best bang-for-your-buck LVPO currently on the market as it delivers good quality glass, a reliable adjustment mechanism, and a lot of nice features at what is pretty much the bottom end of the pricing spectrum for an optic that will likely stand up to duty use.

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The optic is heavy, but the true 1x setting allows quick use at room distances while the 6x setting is incredibly useful for engaging even small targets at 300 yards or beyond. Mated to the pictured Sionics rifle, the combination allows me to hit MOA sized targets at distance with the right ammunition:

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To be clear, this is not a precision setup. While the rifle is certainly very accurate with the right ammunition (contrary to what you read on the internet, a legitimately sub MOA rifle is pretty rare to stumble on) and the 6x magnification setting allows stretching out to essentially the maximum effective range of the rifle, it’s possible to get a dedicated precision 5.56 gun that will shoot .5 MOA or better. You can then mount a lot more glass on top of the rifle and make very small groups at 500 yards and beyond.

That true precision rig, however, is going to be heavy. And at least double the cost of my already somewhat expensive setup. At the end of the day even the expensive precision rig is still going to be shooting a 5.56 projectile that is profoundly impacted by wind and certainly isn’t the greatest performer in terms of terminal ballistics beyond 300 yards.

In a 5.56 rifle I am looking for a good general performer. A package that will let me use the rifle effectively at typical defensive ranges that we see inside the United States, but that I can also use to reliably put down the occasional coyote or feral hog at distances still within the performance envelope of the 5.56 cartridge. As a general purpose rifle that’s a pretty darn good specification and the pictured rifle exceeds it.

Of course, if you ask someone how much magnification they want or how much range they want, the immediate answer will be “MORE”. There are now 1x-8x and even 1x-10x scopes on the market. More is better, right?

Not necessarily. There is no free lunch when it comes to these things. The more magnification you have on your optic, generally the more restrictive the “eye box” becomes. More magnification also tends to increase the expense and weight of the optic. Although Night Force’s 1x-8X is still lighter than my Viper PST-II despite the extra magnification, it is also more than double the price.

I’m sure the Night Force is a great optic, but I’m not so sure I’d shoot twice as well at distance with it even with the extra magnification it offers.

As I said, it’s not a precision rig…but it would be perfect for dealing with the sort of problem LAPD faced in North Hollywood in 1997.

…and that’s really the point, isn’t it?

The 5.56 loaded properly is splendid as a defensive option at the ranges typically used in the United States. It is, after all, an intermediate range cartridge. It can certainly be lethal at extended ranges, but if you routinely need to kill animals at longer ranges or if you have to routinely engage lethal threats at longer ranges you are probably best served by a different cartridge altogether.

To borrow a well-established phrase, mission drives the gear train. Understand what it is you are trying to accomplish with your rifle. If you are building a rifle for a specific purpose then by all means measure each possible component of the build in terms of how it helps achieve your end goal.

If, on the other hand, you are looking for a capable general performer that can do self defense at close range but still allows positive identification and good precision at distance, don’t get lost in the staggering number of options available on the market today. It helps to remember the intended purpose of the intermediate range rifle. Try to avoid forcing it into a role it was never intended to fill.

Your Colt 6920 will never be a true precision gun at 600 yards and your true precision gun will never be great at CQB distances…and that’s fine. Every equipment choice is a compromise in some form or fashion. Just pick the compromises you can actually live with.

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!