If the AR-15 is the king of the rifle world then its progenitor, the AR-10, in all of its many variations is certainly the queen.
While the shooting world is benefiting from downsizing bore sizes to sub .30 caliber there is still a valid need and, frankly, plenty of desire for larger rounds capable of delivering greater power at longer distances then 5.56mm.
For that reason, along with the advent of intermediate calibers that provide exceptional performance at long ranges “large frame” AR-10’s are all the rage.
But with the desire for greater power and greater range comes the desire for a better optic which will enable the shooter to see better, and thus shoot better at these long distances. Optics that enable precise long range shooting are an integral part of the shooting system for those seeking to push the envelope.
On the other hand, we are seeing AR-10s being used with shorter and shorter barrels akin to the heavy carbine category of old. These rifles might be better served with a scope that offers more modest magnification, or perhaps even a red dot or similar reflex sight.
No matter what kind of AR-10 you have and no matter what your objective is with the rifle you can be assured that there is an optical solution that you will feel right at home with.
Today I will share with you some considerations and wisdom I have picked up in my travels over the years when it comes to outfitting your big bore AR.
What Can an Optic Do For You?
Considering the size, reliability and performance of modern optics there is no shooting situation where an optic is not an advantage so long as the shooter is familiar with its use.
Any optic will enable the shooter to aim with more precision and more quickly than they could with iron sights at an equivalent range. Different categories of optic accomplish this in different ways.
Any single plane electronic or prismatic sighting system, be it a holographic sight, red dot sight, reflex sight or whatever (commonly called RDS, for “red dot sight”) accomplishes this by furnishing the shooter with only a single sighting apparatus on a single plane.
This reticle could be a crosshair, a triangle or some other icon.
What is more, aside from eliminating the need to superimpose two separate sight components (e.g. the front sight and the rear sight), and then align them with the target while maintaining their relationship, any of these RDS systems only require that the shooter focus on the target before placing the reticle where they want the bullet to go before breaking the shot.
One should not discount the ability to maintain a target focus compared to a site focus for overall awareness.
The other major category of optics, magnified optics (telescopes), work in principle by allowing the shooter to see beyond the normal biological limits of the human eye.
Plainly stated, they allow you to see really far away and, compared with a traditional telescope or spyglass, the scopes we place on our guns have reticles and adjustments allowing us to precisely determine our point of aim at these extended distances.
The ability to see the target clearly even when it is very far away and precisely adjust our point of aim is what enables us to achieve far greater accuracy then we could using irons alone.
Compared to RDSes, any telescopic sight requires significantly more investment on the part of the shooter in order to maximize it.
Compared to shooting at close ranges with a simple dot for a reticle, a shooter must now learn and become aware of the effects of ballistic trajectory, holds and other fundamentals in order to deliver and maintain accurate fire at a greatly increased range.
Also, it should go without saying the magnification that lets telescopes excel at long distances is a hindrance at short range for obvious reasons. One should also keep in mind that there are many sighting systems that can afford you benefits from each category while remaining competent in the other.
Which one is right for your AR-10 can only be determined after careful consideration of your needs and determining your ultimate objective for the rifle. I cannot tell you what that objective is but I can help you figure it out if you are uncertain. We will do that in the very next section.
(If you just came for the author’s recommendations so you can own your friends on social media, skip on down to the last section for the picks)
What Are YOUR Requirements?
I’m not going to make any recommendations on any kind of optic until we take the time to help you figure out exactly what your needs are. Your specific needs, as a shooter of your rifle, and nobody else’s.
Playing follow the leader or tactical Barbie dress up just because an industry influencer uses model X or brand Y is not necessarily a guarantee of getting a good outcome when equipping your rifle.
Yes, as long as you’re listening to good people you can learn a lot about the subject matter at hand, and probably be assured of buying quality gear, but it does nothing to change the fact they don’t have your problems, and probably don’t have your usage context.
And context is everything. The requirements of a full-time hunter carrying an AR-10 carbine into the woods who also keeps that same rifle loaded for defense of his homestead are entirely different from a police sniper pushing a post on an asphalt rooftop waiting to put a pill into a hostage-taker’s head with atom-splitting accuracy.
That police sniper’s usage context is entirely different from a competitor trying to win a Heavy Metal-class three-gun competition where loss or victory is measured in milliseconds. If you aren’t doing what those guys are doing why would you want to use what they are using?
I don’t want to get too far into the weeds and give you a bad case of analysis paralysis; there are enough nasty germs floating around today.
Instead, I want you to think long and hard about what exactly you were going to be doing with your rifle, and what you need your rifle to do for you in that situation.
Consider the following criteria:
What is the rifle going to be used for? Home defense or defense of a large parcel of land? Hunting? Competition? Do you just want a general purpose big bore AR?
There is no wrong answer, but determining what the primary purpose of the rifle is will largely indicate what type of scope is best for it. Be honest about your needs and purchase according to the rifle’s primary purpose, not some fringe one-in-the-million instance or encounter.
Broadly speaking close ranges favor the RDS while long distances or extreme precision requirements mandate a telescope.
Based on the rifle’s intended role at what ranges will you typically be shooting? 100 yards, maybe 200?
Or perhaps far beyond even that, 300, 400, 500 yards. Even farther? Again be honest. Lots of hunters want a rifle and scope combination that can drop a deer or some other critter at 600 yards all day long and twice on Sunday, but those shots are vanishingly rare in most places.
If all you do is hunt in the woods, assuming you are not shooting across cropland or down a stand of high tension power lines, you will probably never even see a 200-yard shot in your life, much less three hundred and beyond.
For certain applications, namely self-defense at close range or shooting at 100 through 150 yards without need of hair-splitting precision, an RDS is absolutely the first choice, typically, because they lend themselves to fast, accurate both-eyes-open and heads-up shooting.
This is an essential trait fore close and fast work, especially self-defense shooting. If you need more precision or time constraints are not a primary factor more magnification can definitely contribute to better shooting even at intermediate distance.
Good optics of any kind cost money. You can easily drop several hundred dollars on a quality RDS, but you could also very easily drop more money on a high-end telescope then you spent on the rifle and all of its equipment. No joke!
Like most things in the gun world, you really do get what you pay for, and bargain-basement Chinesium optics aren’t even worth installing on your gun for a weekend of plinking since they will invariably break, lose their zero, or otherwise let you down.
If you are on a budget, a good option for reliable performance while keeping costs down is to consider a mid-grade RDS or a traditional telescope from a good manufacturer that is fixed power and otherwise lacking and all the bells and whistles. As with everything else, reliability should come first.
Size / Weight
The more weight you add to your rifle the more fatiguing it is to carry around, and that goes double for keeping it mounted to your shoulder waiting to break a shot. Lighter, leaner rifles are a joy to carry but might not be as stable as a heavier one.
You should always seek to keep weight down if at all possible, but one sure way to start spoiling the balance of an otherwise handy rifle is by putting too large of a scope on it than is required for your purposes.
Most RDS are not so heavy or so bulky that they will make a big difference, but telescopes are another matter, especially after you factor in the weight and bulk of rings or bases.
Don’t answer these questions if they aren’t valid for you; I just want you to get thinking, and defining precisely what it is you’re going to be doing with the rifle, and what kind of performance you need from it so you don’t make a suboptimal choice.
The Best Scopes for Your Money
Below is a selection of my favorite optics on the market in both categories discussed above. No matter what kind of optic you prefer or can afford, there is something on this list that will serve you well.
- Aimpoint Comp M5 – Aimpoint’s current flagship RDS. Excellent battery life (years) provided by common AAA. NV compatible, small footprint, and absolutely bombproof. Come the apocalypse this thing will still work. Costs a mortgage payment.
- Aimpoint PRO – The classic Aimpoint sight revised for the new decade. The same familiar profile of the Comp M2/M3 series, now with a nicer price point. Includes an excellent no-tools mount that returns to zero. A nice inclusion at this price. The best sight in its price range.
- Trijicon MRO – An all-American RDS. Excellent ruggedness and overall quality. Modestly priced. Lenses have a distinct blue tinge, but this should not be a deal breaker.
- EO TECH HWS – One of the O.G.’s in the holographic gunsight sector, and still extremely popular. Large square lenses and excellent reticle make target acquisition and tracking a breeze. Be aware that this company is scandal-ridden, and plenty of seasoned gunhands find them unreliable compared to others in price range. Still, they have many proponents.
- Vortex AMG UH-1 – AKA the Huey. A new contender for the holographic category crown. One of my new favorites. This sight has a wicked good reticle, clear lenses, and better ruggedness and durability from a company that doesn’t suck. What is not to love?
- Leupold VX-6HD 3-18×44 – An incredibly good, robust scope for long distance applications that still provides ample low power usability for closer work. Virtually no weaknesses, but it is kick-you-in-the-teeth expensive.
- Vortex Razor HD Gen 2 1-6×24 – A terrific all-around LPVO for the money. Good glass, excellent on a carbine. Illumination could stand to be a little brighter, but the latest generation offerings are surprisingly light so I’ll let that slide.
- Bushnell Elite Tactical DMR II 3.5-21×50 – In the early aughts, Bushnell was derided for making fun gun-grade glass and little else, a far cry from their proud history. Those days are over, and though they are not quite world-class yet they are climbing fast. Their new DMR II series variables offer an awful lot of optic for a surprisingly low price, and show surprising reliability. I wouldn’t take it into a life or death situation or trophy hunt of a lifetime, but these are fine choices if you are on a budget.
If none of these are what you’re looking for, I found an even bigger list online of the best AR-10 scopes for the money, with pros and cons for each.
Next, time to dig in to the nuts and bolts of magnified optics versus red dot sights.
Anytime people start considering a sighting system for a .30 caliber or other “plus size” rifle they immediately start gravitating towards a magnified optic.
It seems to make a certain amount of sense: a bigger bullet that is more powerful and can nominally go farther than a smaller one can be maximized by employing a sighting system that will allow you to see farther, and thus aim better.
Despite the advances in modern materials, construction techniques and design the rifle scope has remained more or less unchanged over the long centuries since its introduction.
The big-ticket features that will help you determine which scope are right for your rifle generally center on magnification and whether that magnification is fixed or variable. This is usually expressed as a series of numbers for quick recognition, for instance 10×40, 12×50, 3-9×40 or 1-8×24.
In these examples, the first number or the first two numbers indicate the magnification or zoom of the scope expressed as power, with the second number after the dash indicating the upper end of that magnification on a variable magnification scope.
The last number after the ‘x’ shows you the diameter of the objective lens in millimeters.
A larger objective lens increases the overall height and bulk of the optic when it is mounted to the rifle, but it allows more light to be transmitted to the shooters eye, thus improving the clarity of the image. It also typically allows a better field of view at a given magnification than a scope with a smaller objective lens.
Cost is a certainly a factor here, as all things being equal, the more magnification you have, the larger and heavier the scope will be. Variable scopes always cost more than equivalent fixed power scopes of the same quality.
The same goes for objective lenses, with larger scopes costing more. It is possible to get a higher quality scope with less overall features for the same money, and this might be worthwhile if you have a hard ceiling on expenditure for your telescope; you’ll just have to work around the lack of flexibility.
Depending on your application, there are other important factors you should investigate before you choose any scope, namely the eye relief, type of reticle, and whether or not the reticle illuminates by any means.
- Eye Relief: The distance your pupil must be from the eyepiece of the scope to see the full and complete image transmitted by the scope. This may be strict or forgiving, meaning you might need very precise placement of the eye on some scopes or you have some wiggle room on others. This space is called the “eye box” in shooter parlance. A scope with a strict or tight eye box requires you to be far more precise with your head placement to employ the scope properly which might be a liability for closer, faster shooting.
- Reticle: The aiming point inside the scope. Can be simple or complex and found in any number of shapes, the most traditional a crosshair or modified crosshair though chevrons, “plus”, horseshoe and post reticles are all extant. The best scopes for precise long distance shooting often have ranging aids built in that can help with holds, wind calls and more. These “Christmas trees” (named for their appearance) visually complicate the field of view in the scope, but are a great aid for long range shooters.
- Reticle Illumination: A mechanism that lights up the reticle and any associated ranging aids or bullet drop compensators inside the scope. Typically battery-powered, but could be lit by radioactive isotopes or fiber optic light transmitters. Allows one to add contrast to an otherwise black reticle so you can use it in low-light conditions or against a dark background. Unlike a red dot sight, a telescope will not lose its reticle entirely just because it loses the power source for its illuminator.
Is a Magnified Optic Right for You?
Generally speaking, a great all-around choice for a magnified optic on an AR-10 is an LPVO, or “low-power variable optic”. These are excellent, all around rifle scopes that are starting to rule the roost, and not just on .30 caliber rifles.
These optics provide plenty of magnification for mid-range use, typically anywhere from five to eight power at maximum and many of them will dial all the way down to true one power or just a tad over, making them nearly as adept at fast close-quarters shooting as a red dot.
The only disadvantage of these optics is that they are typically expensive if you want to get into a high-quality version and they are somewhat bulkier than traditional fixed magnification scopes.
Resist the temptation to pick up a bargain priced model, as these devices are complicated, even more complicated than traditional telescopes, and highly dependent on the use of quality materials assembled by trained, expert technicians in conditions of exacting quality control.
Sure, your El Cheapo Chinese LPVO might hold up just fine when you baby it for weekend plinking, but the first time you rough it up or expose it to bad weather it is likely to let you down.
An LPVO will certainly cover all of your bases, or at least the bases of most shooters using an AR-10, but what about other applications?
Well, if you are doing strictly long range precision shooting, especially at the same or similar ranges day in and day out you might consider saving some scratch and still getting a high-quality scope by purchasing a fixed magnification scope.
They are seen as somewhat passe today with the preponderance of variables in all categories, but these classic scopes still do what they were meant to do: let you see better and aim better so you can shoot farther or more accurately.
You will give up flexibility with these guys, but only you can determine if flexibility is worth the significant additional expense to upgrade to a variable.
You must also factor in the cost of equally high-quality rings or bases for any magnified optic you purchase. This can often add another couple of hundred dollars easily through your purchase, but is mandatory for getting good service from your scope.
Cheap rings or bases will invariably let you down, rarely hold zero, and are easily damaged. Don’t put a nice scope in flea market-quality rings, no exceptions!
Red Dot Sights
For shots at bad-breath distance at short-range, red dots are unbeatable offering, a tremendous combination of speed of acquisition, target focus, accuracy and excellent tracking of moving targets.
Does the same apply to rifles? Absolutely yes in all regards. But how close is close range for an RDS equipped rifle? That answer varies depending on several factors, but most namely the shooter, the optic, and the size of the target.
For general-purpose applications, an average shooter can do great work with a red dot out to 125 or 150 yards, with seasoned shooters being able to push that significantly.
You’ll never be able to attain the same level of practical accuracy with a red dot at extended distances compared to a telescope, but especially in the context of self-defense shooting or hunting in dense terrain this is not a concern.
Keep in mind that the size of the reticle will also play a part as it might significantly obscure the target at range.
RDS-es also have the advantage of being extraordinarily tough and robust, even though they are battery-powered. But lose power and you’ll have no reticle.
For some of the old guard, this is a deal-breaker even though it shouldn’t be; modern RDS optics often have battery lives measured in years, and we are seeing an increasing amount of technology find its way into these sights even as they get smaller and smaller.
Among such wondrous tech are solar power backup cells and battery conservation technology that puts the site to sleep when it has not moved for an extended period, but will still wake it up instantly at the slightest vibration. Good stuff!
A big advantage when it comes to shooting an RDS is that the majority of them are effectively parallax free and do not suffer from the eye relief issue that magnified optics due. This means that, even with an imperfect head position on the stock, wherever you see the reticle is where the bullet will go.
Features to consider on prospective RDS-es include brightness settings, NV capability, mechanical offset (base height) and type:
- Brightness Settings: How bright is the reticle, how many brightness settings does the sight have and how are they adjusted? Since the reticle of an RDS is your eyes’ only interface with it that matters, you have to get this right. Some sights even on their brightest setting are inadequate for fast acquisition in daylight. Some sights don’t have too much graduation between brightness settings leading to a “Goldilocks” situation where it is either too damn dim or too damn bright. Also, how the brightness setting is adjusted matters: Does it auto adjust using a photocell? Does it use click buttons or a knob type rheostat? If you need to change your brightness settings quickly on the fly in order to set up a better shot or deal with changing conditions, this stuff matters.
- NV Capability: Is the sight night vision capable? Meaning is it compatible with night vision goggles or monoculars? If it isn’t, any of the brightness settings will look like giant fireballs through your night vision device. It only matters if you plan on using it in conjunction with night vision or seriously think you might in the future.
- Mechanical Offset: Most red dot sights you will purchase today can be placed on different bases to achieve a higher or lower position over the bore of the rifle. Colloquially called height over bore, this is more properly called mechanical offset. Although not entirely down to preference, different placements do have different advantages. For close range, combative shooting a taller mount or just a taller sight might work better since it allows you to keep your head more in an upright position. This is also vital when using a protective mask. For more traditional shooting a lower offset is often best and makes zeroing as well as learning your holds a little easier.
- Type: Holographic. LED. Prismatic. Is there any difference? For most practical shooting purposes, no. But it makes a big difference when it comes to battery life. Holographic sights are laser based, and even with all the advances in power management and efficiency technology they are still battery hog. LED’s lead the way in battery life even if they are not as nice optically compared to holographic sights. Don’t let either-or dissuade you from choosing a sight that checks all of your boxes, but be prepared with plenty of extra batteries if you choose a holographic sight! Prismatics are rare, and are not technically red dots at all; instead they have their reticle etched into the glass akin to a traditional magnified optic and illuminate it via the same way even though they feature no magnification themselves.
Is an RDS Right for You?
Red dot sights have been ruling the roost in the gun world for some time now, approaching total ubiquity on long guns and they have long been making constant strides on handguns, with many manufacturers now offering optics-ready packages on their flagship pistols.
Why is this? Simple: An RDS is a total replacement for iron sights. And like iron sights red dots do their best work at comparatively close range.
If you are planning on rocking your AR-10 within 200 yards, or 150 yards on the near side, you can make a very good argument for a red dot sight in lieu of a magnifying scope, especially if the rifle is primarily defensive in nature, ala a heavy carbine.
Some people get wrapped around the axle thinking that only a magnified optic belongs on a .30 caliber or similar rifle. I am not sure why this is; the optic should serve your purposes, not the nominal role of the rifle as viewed today.
And something those long-distance shooters aren’t telling you is that 7.62 NATO has a nasty pig of a trajectory, especially compared to 5.56mm, and it’s more contemporary competitors like the 6.5 Creedmoor.
If you aren’t shooting that far you might not need a magnified optic at all, and plunking one onto your rifle with the assumption that you’ll be reaching out with regularity to 600, 700 or 800 yards is just foolish.
As I mentioned above, a low-power variable optic is the do all tool for most rifles, but they come with a significant price tag. If you’re sticking with a generalist role for your rifle, especially at shorter ranges, you can be well served by an RDS.
An AR-10 will serve you best with scope on it, and no matter what your objective happens to be and what conditions you’ll be using your rifle in, there is an optic that will do the job.
From the close range supremacy of a red dot to the extended reach of a big, cyclopean rifle scope, optics are always a major performance enhancement in any shooting discipline or activity.
Take some time to digest this the info presented, and you’ll be assured of getting the right scope for the job.
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.
1 thought on “How to Choose an AR-10 Tactical Scope”
Optics for a tactical rifle, regardless of caliber, is a handy item to have. However, I am a strong proponent of being skilled with iron sight use before learning to use an optic (electronic or plain old magnified optical types). If you can’t hit your target with irons, optics are not going to create magic for you, and even less so if the optics breakdown.
Optical sight use on combat rifles has created a significant argument in the Marine Corps community. Many old Jarheads (me included) believe recruits should not have an optical sight during initial marksmanship training. Since optics are standard now in the Fleet, recruits do need training on them, but it should be at some point after initial marksmanship training using only iron sights.
My AR-15 and HK-91 both have holographic sights, and the AR has a 3X magnifier. But I’ve been shooting iron sights on combat rifles since 1971 (starting with an M-14), including comps, and optics are a fairly new thing for me. I can still shoot bulls at 500-yards with irons on both rifles, although at my age, I’ll admit some magnification is handy. I’m certain I can still do the same with an M-14 too. I do also admit, needing to shoot 500-yards where I currently live is unlikely, but 200-250 yards is not.