1. science
2. physics
3. optics

One of the advantages of tubeless sights is that they work
even when shooting from unusual or awkward positions, where
eye relief is not consistent.
ALTERNATIVE AR-15
OPTICS AND MOUNTS
SEEING THINGS FROM A DIFFERENT ANGLE
By James Tarr
T
he days when shooters could successfully argue
that optical sights just weren’t robust enough
for duty rifles are gone. Delicate scopes for ARs
don’t survive in our current environment, and most of
the models that have succeeded have proven themselves
in combat.
Iron sights are, and probably always will be, more durable, however optical sights (magnified and otherwise)
provide so much of an advantage in both speed and precision over iron sights that they are now the preferred sighting system for AR-15 type rifles.
Most people think of two separate and distinct types
of optical sighting systems for ARs, non-magnified red
dots and traditional “tube” scopes offering either fixed or
variable magnification, mounted on the 1913 rail atop the
receiver. Those simple two are far from the only dishes
on the AR optics menu. Let’s take a look at a few nontraditional options when it comes to AR optics.
The big names all produce excellent scopes for black rifles, but Tarr
says some of the more offbeat selections have real advantages.
nell Holosight. Jerry was local to the Detroit area, as was
the company making the sight, and that first version offered several different reticles, including the now combatproven circle/dot. The current generation L-3 EOTech
HoloSight still has a few of the same lines as that first
prototype I saw, and what made it successful then hasn’t
changed (www.eotech-inc.com).
Unlike many competitors, the EOTech HoloSight
is not a tube sight. Users instead look through a rectangular window that gives them a near unlimited nonmagnified field of view. The EOTech reticle is a 65 moa
circle around a 1 moa center dot, which allows speed,
accuracy, and range estimation, and cranked all the way
up, it is more than bright enough for daytime work in
the desert.
Everything has its price, however, and that big bright
reticle sucks the batteries dry very quickly, even when using models fed by AA batteries. Compared to the ubiquitous Aimpoint, most EOTechs are bigger, heavier, and
have only a fraction of the battery run time, but it is the
The Forward-Mounted EOTech
I was at a local USPSA match circa 1995 when world- field of view and unbeatable reticle that keeps EOTechs
champion competition shooter Jerry Barnhart showed up on the rifles of soldiers going into harm’s way.
I was told recently by someone in the know that the
with a prototype holographic red dot sight on his race
pistol. That prototype became the first generation Bush- EOTech is commonly used by SF operators even with its
short battery life. I imagine they throw in fresh batteries
every time they head out, and have spares on them.
“Scopes” have been mounted at the rear of rifle receivers for centuries, and most people clamp their red
dot sights in the same place, on top of their AR receiver.
Occasionally, however, you might see a red dot mounted
far forward on a rifle, way out on the handguard close to
the front sight. This is sometimes referred to as a “Scout”
mount, and there are several reasons this is done.
A forward-mounted non-magnified red-dot seems to
point more naturally when engaging close targets where
speed is more important than precision. Your sight is
closer to the target as well as the end of your rifle, and
putting the red on the target, especially if it’s a moving
target, is quicker and easier once you become familiar
with the setup.
This works with all red dot sights, but the EOTech’s
tubeless construction and big bright circle/dot reticle combination seem specifically suited to this forward mounting
technique. Also, one of the wonders of modern red dot
technology is that the reticle of the EOTech appears the
same size to your eye no matter the distance from it.
With the sight mounted forward, the circle/dot reticle
is nearly half as wide as the EOTech’s window. Hon-
Mounting red dots, especially
EOTechs like this EXPS3, toward
the muzzle makes them seem to
point more instinctively and can
speed up target acquisition time.
One of the wonders of modern red dot
technology is that the reticle of the
EOTech appears the same size to your
eye no matter the distance from it.
estly, mounting an EOTech forward on an AR makes
the reticle, in a kind of optical illusion, look larger to
the eye.
Putting a red dot, especially an EOTech (the smallest
EOTech Model EXPS3 weighs 11.2 ounces) out near the
front sight will reduce muzzle rise to some small degree
because of the weight holding down the muzzle. However,
to mount an EOTech or any sight forward usually necessitates a railed handguard, and rails add weight. Railed
handguards often wear vertical grips, sling swivels, or
flashlights, so once a sight is clamped out there the end
result can be a very muzzle-heavy rifle.
Meprolight M21
When talking non-magnified red dots, most people
think of battery-powered sights, but tritium/fiber-optic illuminated reflex sights free of batteries have been around
for decades, and their designs have been improving as well.
I have owned a first-generation Trijicon Reflex sight
since Bill Clinton was in office, and it is great for many
reasons—first and foremost is that it is not powered by
any batteries. It is always on, and I don’t have to worry
about forgetting to shut it off. In complete darkness the
tritium illuminates the reticle, although after 15+ years I
have to admit my tritium has lost a lot of its brightness.
The problem with this sight, and many others of that era,
is that while they work great outdoors, indoors or in variable lighting, they leave much to be desired.
If I stood in a dimly lit area (indoors for example) and
aimed my reflex-sighted rifle at a brightly lit area, the
reticle more often than not completely washed out. The
fiber-optic in the sight just wasn’t picking up enough ambient light where I was to make the reticle pop out against
the brightly lit background. First generation reflexes had
minimal fiber-optics on the front of the unit, which made
it very robust, but the brightness of the reticle suffered.
Such is not the case today.
The Meprolight Mepro 21 (M21) is an Israeli-made reflex sight imported into this country by The Mako Group
(www.themakogroup.com). Big and robust, you’ll see the
M21 on top of many M4s in the Israeli army as well as
their relatively new bullpup assault rifle, the Tavor TAR21. In addition to having a protected fiber optic collector
running from one side of the sight, across the top, and
down the other, to make better use of any and all available
light, I recently discovered this sight was available with
several different reticles.
My old Trijicon reflex has a 12.5 moa triangle reticle,
and this is a great compromise reticle that allows for precise aiming using the point of the triangle while still being
big enough to work well in CQB applications. The M21 is
available with numerous reticles—4.3, and 5.5 moa dots, a
triangle, and an “Open X”, I obtained one with a “Bullseye” reticle as I think the EOTech’s circle/dot is the best
non-magnified combat reticle design and wanted to see
how the M21 compared.
The M21 has a 30mm lens and is 4.53 inches overall,
with a weight of 8 ounces not including mount. It seems
heavy for its size, but the aluminum it is made of is not
thin or delicate—this is a combat sight. Windage and
elevation are adjusted by means of external click adjustments, one click equaling 2 inches at 100 meters.
The Meprolight M21’s reticle is illuminated during daylight hours by a fiber optic collector exposed on the top,
sides, and front of the optic. The reticle brightness adjusts automatically—the more light hitting the sight, the
brighter the reticle gets. The fiber optic itself is protected
by a gray plastic cover that is apparently opaque.
The rest of the sight is constructed of aircraft grade
aluminum alloy. At night the reticle is powered by tritium,
and while the manual says the sight is NVD compatible,
I found the tritium-powered reticle in complete darkness
so bright I wondered if it might be a little too bright when
used with NVD. I’ve always found Meprolight’s pistol
sights the brightest when compared with other manufacturers of tritium inserts, and apparently their optical
sights follow that same pattern.
The front of the optic is threaded to accept a killflash,
and the optic sent to me had a rail mount attached. This
mount had two throw-levers adjustable for tension, and
allowed me to mount the reflex securely to an AR in a
matter of seconds. Numerous other mounts are available
for mounting on other weapon platforms.
The “Bullseye” reticle, in fact every reticle pattern they
offer, is pale orange in color (Meprolight states it is redorange but my eyes didn’t see any red) and consists of a
segmented circle around a center dot. The circle is actually four curving arcs separated at 3, 6, 9, and 12 o’clock.
The exact dimensions of the Bullseye reticle are apparently some sort of Israeli state secret, because not only are
[Cont. to page 9]
The Meprolight Mepro 21’s
reticle is illuminated during
daylight hours by a fiber optic
collector exposed on the top,
sides, and front of the optic.
Several different mounts are available for the Mepro 21, including this dual
throw-lever unit for receiver rails that allows easy installation and removal.
The gray polymer windows on the M21
protect the fiber optic collector, which
powers the reticle in daylight. Windage and elevation are click adjustable.
The Meprolight M21 is available
with several different reticles,
including this circle/dot. It’s
bright, but Tarr wished the circle
had a larger outside diameter.
[Cont. from page 5]
they not listed in the owner’s manual, they are nowhere
to be found anywhere, and even my contact at Mako Defense, the sole U.S. importer of the sights, couldn’t track
them down.
Using an old-fashioned technique (my eyeball and a
grid target at 100 yards), it appears as if the outer diameter of the circle is 30 moa, and the center dot is 4 moa.
The circle is fat, approximately 6 moa thick, and to my
eye resembled a donut more than a ring.
For testing I mounted the M21 on a lightweight carbine I built recently after I realized I didn’t have a personal AR manufactured in this century. It followed my
philosophy of “as short, light, simple, and cheap as possible”, and features a BCM top end with 14.5-inch barrel and mid-length gas system over a Stag Arms lower
and Magpul MOE furniture. As far as I’m concerned,
it has everything you need in a self-defense carbine, and
nothing you don’t—unloaded with no optic, the carbine
weighs a mere 6 pounds, 4 ounces, and with the M21
mounted it was almost exactly 7 pounds.
While taking photos for this article on an overcast day,
with light drizzle, the M21’s reticle was as bright as a battery sight set at the proper brightness for that environ-
ment. In direct sunlight it is correspondingly brighter,
and very easy hit man-size targets with at speed out to
100 yards.
I found I was using the 30 moa donut as a huge dot in
speed drills out to that distance. Farther out, the donut
tended to obscure the targets a little, especially when it
was very bright in comparison to the target, because there
wasn’t enough unlit space between the ring and the dot.
Even with the improved fiber optics, the reticle on the
M21 is not as bright indoors as you’ll find on a batterypowered sight, but it is better than on previous generations. I think this is why the circle section of the bullseye
reticle is so fat, because otherwise it might wash out in
marginal light, but I still wish it had a larger outside diameter, either 60 or 65 moa.
Combined with the 4 moa dot, the center of the reticle
is a bit crowded when it comes time for precision shooting, and I wish I had an opportunity to try some of the
other reticles available, such as the triangle or the Open
X, which intrigues me. No matter which reticle you
choose, the M21’s battery- and switch-free operating system has much to recommend it, and with an MSRP of
$563.25 it’s quite a value.
The Offset Red Dot
While many in the “tactical” arena seem to live to denigrate competitive shooters, the fact of the matter is those
competitors take new and unproven equipment and beat
the snot out of it. Anything that doesn’t break (or breaks
last) is then improved and, quite often, ultimately adopted by the military. Competitive 3-Gun shooters are one
of the main reasons our soldiers are now fielding M4s
topped with Aimpoints and EOTechs.
The 4X ACOG is an excellent, battle proven sight,
very useful when engaging targets at distance (Afghanistan anyone?), but it leaves a lot to be desired when it
comes to CQB. Trijicon began offering ACOG scopes
with mini-red dot sights mounted atop them at the
factory at the request of SF operators—years before
that, competitive 3-Gun shooters tasked with engaging
both distant targets and close-in fast moving ones invented the concept. Shooters quickly discovered, however, that mounting a red dot above the ACOG completely eliminated any hope of obtaining a cheek-weld
on the weapon.
Numerous alternatives to the top-mounted minired-dot were tried, and the most successful has been to
mount the mini red-dot (or back-up iron sights) off to
the right side of the main optic at about the 2 o’clock
position. This may sound awkward to use but is anything but. The shooter just rotates the rifle off to his
weak side while keeping his same cheek weld and shoulder mount, and the mini-red-dot rolls right in front of
your eye.
Just prior to starting this article I took a tour of Black
Hills Ammunition, and had an opportunity to shoot the
“spotter’s rifle” BHA President Jeff Hoffman sometimes
uses when working as a sniper for the Pennington County S.D. Sheriff ’s Department’s response team. This AR15 is an 18-inch barreled SPR loaded with (of course)
Black Hills ammunition.
His main optic is a Nightforce 2.5X-15X which, even
when cranked down to 2.5X, does not have a big enough
field of view to be useful inside 40 yards. He therefore
has a secondary optic (in this case a micro-Aimpoint)
mounted at the 45˚position. I had no problem at all
ringing a steel silhouette offhand at 100 yards using the
offset Aimpoint.
I have seen a number of different methods for mounting these small red-dots off to the side of magnified
optics, from extra scope rings with rail sections to dual
To use an offset mount, you roll the rifle
to your weak side with a simple twist.
This feels much more natural than
you might think, given the odd angle.
There are many ways to attach a minired dot in the offset position, but Tarr
says the Predator Tactical Gen 2 Burkett
Offset mount is the simplest and best.
ELCAN Specter DR and OS4X
ELCAN is an acronym for Ernst Leitz Canada, and Raytheon ELCAN Optical Technologies of Canada has been
producing military optics for the Canadian government
since the 1950s. For most American consumers, the most
recognizable product ELCAN has fielded is a 3.5X scope
adopted by the Canadian military. This compact roof prism
optic is most usually seen with a rubberized cover atop ARs,
however the U.S. did adopt a modified version of the sight
to use on M240 and M249 LMGs.
What has gotten tongues wagging the most is ELCAN’s
legendary Specter DR scope. I first heard about this scope
long before I was ever able to get hands on one, as it was all
ELCAN could do to keep up with the small unit military
orders for this unique product. If there is such a thing as
an “Ultimate Combat Optic” for the AR-15 platform, the
Specter DR is as close to it as you’ll currently find. Now
that ELCAN has caught up on their orders to the troops
heading into harm’s way (including USSOCOM), it is now
possible for consumers to actually buy one.
First, while the Specter DR is a 1X/4X, it is not a traditional variable power scope. It is a switch power scope—
you have your choice of 1X or 4X by means of flipping
a spring-loaded throw lever forward (4X) or back (1X).
There is a detent so the lever (hopefully) can’t be bumped
Note that I said rifle, not main optic, because the Preda- out of place accidentally while walking with the rifle.
The Specter DR has a simple but effective ranging reticle
tor Tactical Gen 2 Offset Mount has a quick detach base
that clamps directly onto the top rail of your AR. It is low calibrated for the 5.56 cartridge out to 600 meters—specifienough (protruding just 3/8" above the rail) to fit under any cally the 62-grain M855 round fired out of a carbine-length
optic you might be using, and is entirely constructed of barrel. The reticle also features dual LED illumination—
turn the knob counter-clockwise and you get a 6 moa red
thick 4140 hard-anodized aluminum.
If you want to switch main optics, go right ahead, the dot in the center of the cross hairs (1.5 moa on 4X). With
beauty of the PT design is that it is an independent mount, five illumination settings, it is more than bright enough to
and it is reversible for left or right side mounting—in fact, see in direct sunlight, and is NVD compatible. At 1X (and
it can be mounted anywhere there is a rail. The mount fea- it’s a true 1X), with the dot on, the Specter DR basically
tures a platform on the side tilted at exactly a 45˚ angle with works as a red dot sight, and has more than enough field of
view ( a huge 26˚/146.3 feet at 100 yards) to perform in this
wings on either side to protect the mini red-dot.
It is beefy, but because of its size it still only weighs 4 role. At 4X the sight has a generous 6˚ field of view (34.2
ounces. There are versions of the Gen 2 Burkett Offset feet at 100 yards).
Turn the illumination knob clockwise and the crosshairs
Mount to fit just about every brand of mini red-dot including most new models (such as the Trijicon RMR), and I ob- of the reticle light up. While this illumination option is not
tained one which fit the Insight MRDS I had on hand. The bright enough to be noticeable in direct sunlight, it works
great for low light.
mount retails for $139.95.
Shooting an AR with an angle-mounted mini red-dot
The illumination is provided by a DL 1/3N lithium batsight does not feel normal in your hands, on your shoul- tery that provides a minimum of 600 hours of service at
der, or to your eyes, but it does not feel nearly as wrong its maximum setting. The scope also has emergency iron
as you might think, either. You probably won’t be able to sights, “rain sights” per ELCAN’s literature, mounted atop
wring the kind of accuracy out of it as you would with the it. These consist of a peep rear and a post front. Shootsame sight mounted directly atop the rifle, but remember, ing using just the iron sights I found they work fine out to
this is a back-up sighting system to be used at distances about 50 yards, but are a bit coarse for much precision betoo close to use your main optic. As such, this system yond that.
The optical quality is superb, and the scope has a healthy
works very well, and the Predator Tactical Gen 2 offset
70mm of eye relief. Unlike traditional scopes where windMount is the best of the breed.
age and elevation adjustments move
the reticle inside the tube, the reticle
on the Specter DR is fixed, and all adjustments are external and move the
scope on the integral base. Each click
provides .5 moa adjustment. All that
is needed to adjust the sight are fingers
and/or a cartridge case, and once zeroed, the elevation knob can be locked
into place. The base has two A.R.M.S.
QD throw levers and is designed to
mount onto a standard 1913 rail.
This is not an improved hunting
scope: it was purpose built for the military, and looks it. The beauty of the
DR is in its performance, not its flat
black anodized aluminum exterior. At
22.5 ounces it may seem a bit heavy
compared to other offerings, but you
have to remember that weight is all
inclusive.
Once you add the weight of rings
Both the ELCAN Specter DR (front), and the OS4X are relatively compact
units that are generally free of projections that can be damaged in rough use. and bases to other scopes, the Specter
Tarr thinks if there is such a thing as an “Ultimate
Combat Optic” for the AR-15 platform, the ELCAN
Specter DR is as close to it as you’ll currently find.
scope mounts, but not all designs are created equal. When
the red dot mount is part of the main optic’s mount, or
even on a scope ring, if the shooter wants to change his
main tube optic he would then be obligated to buy another
mount for his red dot as well, or another railed scope ring
(if changing to a scope with a different tube diameter).
Scope ring mounts also put the red dot even higher off
the rifle, potentially pulling the shooter’s face off the stock
once again.
The simplest and best-designed 45˚mini red-dot mount
I’ve ever seen comes from Predator Tactical (www.preda
tortactical.com), started by professional shooter Matt
Burkett. Burkett has won just about every 3-Gun title there
is, and PT’s Gen 2 Burkett Offset mount has everything
you need and nothing you don’t to mount a mini red-dot
to your rifle as a back-up sight.
The lever that selects 1X or 4X can be seen at the bottom. There is a detent, and the lever has to be moved
downward before it can be pushed forward or back.
The ELCAN OS4X is designed to compete with the Trijicon ACOG. Like the DR it features external windage/
elevation adjustments for extra ruggedness in combat.
ALTERNATIVE AR-15 OPTICS AND MOUNTS
The Hi-Lux CMR 1-4X24 is an economical
scope that features an illuminated double horseshoe reticle. It is shown here
in an ADM mount on a Barrett REC-7.
DR is not any heavier, and probably shorter (at 6 inches)
than any competitor’s variable-power scope. There are
many scopes out there priced a lot higher than the $1898
Minimum Advertised Price (MAP) of the Specter DR,
but I honestly don’t believe any other scope can touch
the Specter DR in versatility and performance for the AR
platform.
New from ELCAN is a fixed 4X power scope designed
to compete with the Trijicon ACOG. The Specter OS4X
resembles a stripped-down DR, with the same integral
base. It features an etched-glass 800 meter BDC reticle
with dual illumination.
Rotate the illumination knob counterclockwise and the
center of the reticle (a tiny crosshair) lights up on the C1
model. The A1 model features a chevron in the center instead of crosshairs, with the same BDC reticle. Rotate the
illumination knob clockwise and the entire reticle lights
up for use in low light situations. On the sample I was
provided optical quality was excellent, and both it and
the DR were more than tough enough to survive the mild
abuse I put them through.
While not inexpensive, the OS4X at $1199 MAP is
priced in line with the competition, and both sights are
available from ELCAN’s master distributor, Armament
Technology Incorporated (www.armament.com).
Hi-Lux CMR 1-4X24
Thirty years ago there was no such thing as a variable 1X-4X or 1X-6X scope specifically made for the AR
platform, so shooters who realized the advantages that
kind of scope brought to the tactical arena made do with
hunting scopes with duplex reticles. Now the list of companies making low-power variable scopes with custom
CQB reticles for M4s is long and distinguished.
While well respected during the Vietnam era, the Leatherwood brand was bought by Hi-Lux (www.hi-luxoptics.
com) and the last few decades has (justifiably) had a mediocre reputation. With the CMR, this is changing. The CMR
(Close Medium Range) was designed by a Russian engineer specifically for use by Russia’s version of our Delta
Force. The Russians have tested the scope, and not only did
the scope survive their testing, it’s in use currently. As their
funding is minimal, the scope also had to be affordable, and
so it is priced so low many people might just assume it is
junk, especially since it is made in China. Not so, which is
why I’m including it in this article.
The Hi-Lux CMR 1-4X24 shown with the MGM Switchview “cattail” attached. This
lever allows the user more quickly and easily to change the power on his scope.
While not as advanced in their lenscraft as the Germans, the glass now being made in China is excellent, and
the CMR had excellent light transmission and clarity. It
is built with a 30mm tube and comes with flip-open lens
covers. It has an illuminated double horseshoe reticle
with a BDC designed to be used at 4X.
The inside horseshoe is thicker than the outside one,
and glows bright green, as does a center dot, when the
illumination is turned on. The sight is NVD compatible,
and there are 11 brightness settings. While I wish the illumination was brighter (in full daylight it washes out),
the reticle is well thought out.
Many companies are offering scopes with similar features, but the glass on most of them can’t compare to the
Hi-Lux CMR, which is remarkable considering its low
price. For an MSRP of $299.99 it is a value that is hard
to beat.
Scope mounts that align a red dot at or just above the
plane of the iron sights on AR-15s are common, but
when you mount a variable scope with a more detailed
reticle at that height the field of view gets very busy at 1X
if you’ve got a fixed front sight. For that reason I mounted the Hi-Lux CMR for testing in an ADM Recon-H
mount, which puts the scope 1.93 inches above the rail,
as opposed to the 1.4-1.5 inches a standard mount does.
The front sight is no longer in the picture at 1X.
I’ve found that the power adjustment rings on many
scopes are either hard to turn or poorly knurled, so it is
hard to get a grip on them. Many companies are now selling bolt-on levers or “cattails” that enable the user more
quickly and easily to change magnification.
While these initially found favor in the 3-Gun arena,
as more and more of our soldiers carry variable power
scopes into combat they have come to recognize the utility of being able more positively to manipulate their optics under stress.
The MGM Switchview is the best designed scope lever I’ve found. Produced by Mike Gibson Manufacturing
(MGM Targets), the Switchview is just the right size and
shape so that it won’t block the user’s field of view when
not looking through the scope, and simply bolts on with
the use of two Allen-head screws. Constructed entirely
of anodized aluminum, it is offered for most common
scopes, and I discovered that the one made for the Leupold VXIII/Mark IV with illuminated reticle/Bushnell
Elite 6500 also fits the Hi-Lux CMR. (www.mgmswitchview.com).
The number of optics options for AR-15/M4 type rifles
is simply astounding, and I’ve only scratched the surface
of the offbeat ones, but having a lot of choices is definitely better than not enough!
No modification is required to install the MGM Switchview on the scope, and
levers are made to fit almost all types of tactical variable-power scopes.