In this NSSF Video, Ryan Cleckner, a former Sniper Instructor for the 1st Ranger Battalion, defines the term, “Minute of Angle” (MOA) and explains how you can adjust for windage and elevation using 1/4 or 1/8 MOA clicks on your scope. This allows you to sight-in precisely and compensate for bullet drop at various distances.
For starters, Ryan explains that, when talking about angular degrees, a “minute” is simply 1/60th. So a “Minute of Angle” is simply 1/60th of one degree of a central angle, measured either up and down (for elevation) or side to side (for windage). At 100 yards, 1 MOA equals 1.047″ on the target. This is often rounded to one inch for simplicity. Say, for example, you click up 1 MOA. That is roughly 1 inch at 100 yards, or roughly 4 inches at 400 yards, since the target area measured by 1 MOA increases in linear fashion with the distance.
MIL or MOA — which angular measuring system is better for target ranging (and hold-offs)? In a recent article on his PrecisionRifleBlog.com website, Cal Zant tackles that question. Analyzing the pros and cons of each, Zant concludes that both systems work well, provided you have compatible click values on your scope. Zant does note that a 1/4 MOA division is “slightly more precise” than 1/10th mil, but that’s really not a big deal: “Technically, 1/4 MOA clicks provide a little finer adjustments than 1/10 MIL. This difference is very slight… it only equates to 0.1″ difference in adjustments at 100 yards or 1″ at 1,000 yards[.]” Zant adds that, in practical terms, both 1/4-MOA clicks and 1/10th-MIL clicks work well in the field: “Most shooters agree that 1/4 MOA or 1/10 MIL are both right around that sweet spot.”
Zant does note that a whopping 94% of shooters in the Precision Rifle Series (PRS) used a mil-based reticle. However, Zant says: “This does NOT mean MIL is better. It just means MIL-based scopes are more popular.” Zant agrees with Bryan Litz’s take on the subject: “You can’t really go wrong with either (MIL or MOA). They’re both equally effective, it comes down to how well you know the system. If you’re comfortable with MOA, I wouldn’t recommend switching to MIL. I have a few MIL scopes but primarily because they’re on rifles used for military evaluation projects, and that community is now mostly converted to MILS, so when in Rome….”
We recommend you read Zant’s complete article which is very thorough and is illustrated with helpful graphics. Here are the key points Zant makes in his MIL vs. MOA analysis:
MIL vs. MOA — Key Points
There are a handful of minor differences/trade-offs between MIL & MOA, but there are no inherent advantage to either system. Most people blow the small differences WAY out of proportion….Here are the biggest differences and things to keep in mind:
Whatever you decide, go with matching turret/reticle (i.e. MIL/MIL or MOA/MOA)
1/4 MOA adjustments are slightly more precise than 1/10 MIL.
MIL values are slightly easier to communicate.
If you think in yards/inches the math for range estimation is easier with MOA. If you think in meters/cm the math is easier with MIL.
When your shooting partners are using one system, there can be some advantage to having the same system.
Around 90% of the PRS competitors use MIL.
There are more product options (with ranging reticles) in MIL.
Range Card Print-Outs
Zant makes an interesting practical point regarding range card print-outs. He suggests the MIL System may be easier to read: “You can see in the range card examples below, 1/4 MOA adjustments take up more room and are a little harder to read than 1/10 MIL adjustments.”
Swarovski has a new STR 80 spotting scope with an illuminated reticle. That’s right, this new STR 80 spotter has a ranging reticle like a riflescope, with adjustable brightness levels. This 80mm spotting scope can be used for estimating range to targets, using MIL-based or MOA-based stadia lines on the cross-hairs. This allows you to range targets optically, as you could with a ranging reticle in a riflescope.
Revolutionary Reticle “ON”, Reticle “OFF” Technology
The STR 80’s illuminated ranging reticle makes the new STR 80 a fairly unique product among high-end, imported spotting scopes. Thanks to a new technology, Swarovski is the first manufacturer to successfully project a reticle directly in a spotting scope. The reticle (MOA or MRAD) can be activated or deactivated as required. Notably, because the reticle appears via electro-illumination, it can be “turned off” for un-obstructed viewing. So you can have a totally clear field of view when desired, OR a ranging reticle when that functionality is desired. Having the ability to turn OFF the reticle is great — that’s a very intelligent feature.
When viewing targets, the STR 80’s sharp HD (high-definition) lenses will resolve bullet holes at long range. Current Swaro 20-60X and 25-50X (wide) eyepieces can be used with the new STR 80 spotter. Optional accessories include Picatinny mounting rail, digiscoping attachment, and a winged eye cup.
How to Range with STR 80 Reticles
The new STR 80 scope offers a choice of either MOA or MRAD reticles with 15 brightness levels, 10 day levels, and 5 night levels. For convenient ranging, set the magnification level so that the MOA reticle displays ¼ MOA divisions, while the MRAD Reticle displays 0.1 MIL divisions. (NOTE: the reticle will change in size relative to the target at different magnifcation levels. Therefore ranging is normally done at one standard magnification level).
Dustin Woods, Sales Director for Swarovski Optik NA said: “Long range shooters asked for a premium spotting scope with integrated reticle and we have listened. With our new STR spotting scope we now have MOA and Mil-Radian reticle models. Because the reticle is illuminated, the user can have the reticle turned on when they are judging hits and misses but also turn it completely off for an unobstructed view during observation. This product is a real game changer in the precision shooting segment.”
Leupold has just introduced a new second focal plane reticle with MOA-based hashmarks, allowing precise hold-overs and hold-offs (for wind). The new TS-32X1 reticle, is a minute-of-angle (MOA) based system designed to allow for precision shots without the need for dial adjustments. The TS-32X1 reticle is designed to work with riflescopes that employ 1/4-MOA target adjustments or M1 dials.
The TS-32X1 is the first in a family of MOA-based reticles that will cover several magnification ranges. The TS-32X1 will be available for a wide variety of Leupold riflescopes. For $159.99, the Leupold Custom Shop can also retrofit this reticle into many existing Leupold scopes. Adding the TS-32X1 to a new riflescope ordered through the Custom Shop will cost $129.99.
MOA-Based Hashmarks on Horizontal and Vertical Stadia
On the TS-32X1 reticle, a heavy post and thin stadia crosshair features 1-MOA hashmarks on both the horizontal and vertical lines. Every other hash mark on the horizontal stadia is slightly longer, providing quick and easy 2-MOA measurements. There is a number placed every fourth MOA for quick reference.
The vertical stadia is also set up with 1-MOA tics and longer 2-MOA marks. In addition, every fourth mark is numbered, all the way to the complete 32-MOA elevation range. Wind dots in the lower half of the reticle are spaced in 2=MOA increments, both vertically and horizontally.
This new TS-32X1 reticle is currently available for most second (rear) focal plane VX-3, VX-III, Vari-X III and Mark 4 4.5-14 LR/T riflescopes. Existing riflescopes can be retrofitted for $159.99 through the Leupold Custom Shop. To add the TS-32X1 to a new riflescope ordered through the Custom Shop is $129.99.
Product tip from EdLongrange. We welcome reader submissions.
Barrett offers an innovative scope ring set that adjusts to two different MOA elevations through the use of variable-position cross-pins in the rear ring. Barrett’s Pin-Lock® ExRings allow a dual-setting +MOA taper by placing the adjustment pin in one of two locations. To change settings, simply remove the rear pin from one hole and insert it into the other (after loosening side locking bolts*). There are multiple ExRing versions: 30mm with 15/40 MOA settings (#66850), 30mm with 20/30 MOA settings (#66858), and 34mm with 20/30 MOA settings (#66870).
Barrett says the lower 15 or 20 MOA settings are commonly used with canted rails while the higher 30 or 40 MOA settings are for flat rails. Once an elevation setting is selected and the ring’s cross bolts are torqued to specification, Barrett ExRings become a rock-solid mount with the MOA “pre-load” angle best suited to your application. NOTE: Rings come factory preset at the lower MOA setting. CLICK HERE for Barrett ExRing Mounting Instructions (PDF).
These rings are ideal for extreme long-range shooting, offering a huge amount of elevation “pre-load” that allows the shooter to keep his scope in the middle of its elevation range. We’re not aware of any other ring system that allows a quick, repeatable change from 15 MOA preload to 40 MOA (and vice versa), or even from 20 to 30 MOA. The system will work with a wide variety of installations. ExRings will work on both flat and tapered m1913 Picatinny-type rails, and there should be enough clearance for scopes with front objectives up to 70mm in diameter. ExRings are made from tough, T-6 aluminum, hard-anodized to 60 HRC specs. A special “Zero-Gap” clamping system provides a very secure mount.
Barrett ExRings® (Extended Range Scope Rings) Key Features:
• Maximizes the riflescope’s internal elevation adjustment.
• ZERO-GAP offers wider clamping area and maximizes “scope grip”.
• ZERO BACKLASH tongue and groove interface.
• High Strength Aircraft-grade 7075 T6 aluminum.
• 2.5 times lighter than steel.
• Heat-treated steel cross bolt and captured nut for increased strength.
• Hard Anodized with a 60 HRC (Rockwell C scale).
• Both 30mm diameter and 34mm diameter available.
• BORS compatible.
ExRings Prove Themselves in Long-Range Competition
You’ll find an extensive review of the Barrett ExRings on Australian Long Range Shooter Magazine. The creator of that website, Norm Nelson, mounted Barrett Pin-Lock 15-40 MOA adjustable rings on his 7mm F-Open rig. He then proceeded to use that rifle (with ExRings) to win the 2013 Australian Long-Range Championship. Here are Norm’s comments:
“I used [the ExRings] to great effect to win the Australian Long Range F-Class Open competition earlier this year. They enabled me to use a higher magnification scope at the 1200-yard range. I have since bought a second pair and run them on my .375 Cheytac to shoot way out yonder.
The operation and fitting of these rings is quite easy and they provide a strong mounting solution for long range rifles that need an extra bit of elevation. Once mounted to the rail the ring top halves are removed and the side locking plates are loosened. At this time the rear adjustable adjustable pin can be removed if desired and placed into either [MOA position].
These are solid rings designed to withstand the recoil of the big Barrett rifles. In the testing I have done so far, I have not noticed any movement of these rings and would be surprised if I did given their build design and quality.”
*HOW to CHANGE ExRing MOA SETTINGS
Barrett recommends changing the MOA setting after scope is installed on rifle.
1. Remove the two side locking bolts from the rear ring and loosen the two side locking bolts from the front ring using the T27 Torx® end of the supplied L-wrench.
2. Use a 1/8″ pin punch to remove the adjustment pin from the rear ring.
3. Align the corresponding pin hole locations, insert and tap the adjustment pin flush using a pin punch.
4. Tighten all four side locking bolts to 50 inch/lbs or 5.6Nm
Burris Signature Rings with polymer inserts are an excellent product. The inserts allow you to clamp your scope securely without ring marks. Moreover, using the matched offset inserts you can “pre-load” your scope to add additional elevation. This helps keep the scope centered in its elevation range while shooting at long range. Additionally, with a -20 insert set in the front and a +20 insert set in the rear, you may be able to zero at very long ranges without using an angled scope base — and that can save money. (To move your point of impact upwards, you lower the front of the scope relative to the bore axis, while raising the rear of the scope.)
Insert Elevation Values and Ring Spacing
People are sometimes confused when they employ the Burris inserts. The inset numbers (-10, +10, -20, +20 etc.) refer to hundredths of inch shim values, rather than to MOA. And you need the correct, matched top/bottom pair of inserts to give you the marked thousandth value. Importantly, the actual amount of elevation you get with Burris inserts will depend BOTH on the insert value AND the spacing between ring centers.
Forum member Gunamonth has explained this in our Shooters’ Forum:
Burris inserts are [marked] in thousandths of an inch, not MOA. To know how many MOA you gain you also need to know the ring spacing. For example, with a -20 thou insert set in the front and a +20 thou insert set in the rear, if the ring spacing is 6″, the elevation change will be approximately +24 MOA upwards.
Here’s how we calculate that. If you have a 2 X 0.020″ “lift” over a distance of 6 inches (i.e. 0.040″ total offset at 0.5 feet) that’s equivalent to 0.080″ “lift” over 12 inches (one foot). There are 300 feet in 100 yards so we multiply 0.080″ X 300 and get 24″ for the total elevation increase at 100 yard. (Note: One inch at 100 yards isn’t exactly a MOA but it’s fairly close.)
Here’s a formula, with all units in inches:
Total Ring Offset
——————– X 3600 = Change @ 100 yards
Ring Spacing
(.020 + .020)
—————– X 3600 = 24 inches at 100 yards
6
NOTE: Using the above formula, the only time the marked insert offset will equal the actual MOA shift is when the center to center ring spacing is 3.60″. Of course, you are not required to use 3.60″ spacing, but if you have a different spacing your elevation “lift” will be more or less than the values on the inserts.
Angled Weaver-style or Picatinny-style scope rails elevation “pre-load” are commonplace these days. But most angled scope rails are non-adjustable. Cold Shot LLC offers a more sophisticated solution — an adjustable scope base that allows the shooter to “dial in” up to +150 MOA of vertical. The M.O.A.B. system works via a horizontal rotary adjuster with 1/4-MOA clicks, positioned on the rear of the unit. The M.O.A.B. 150 can be mounted on any rifle fitted with a full-length Picatinny Rail, chambered for any cartridge from .22 LR all the way up to .50 BMG. The M.O.A.B. system works well on AR rifles — when installed on any flat-top AR, the M.O.A.B. eliminates the need for extra-high rings or riser blocks.
With the M.O.A.B. 150, a shooter has more than 150 minutes of angle (i.e. vertical adjustment) calibrated in 1/4-MOA clicks, with a handy zero-stop. This allows you to stay centered in the vertical elevation range of your scope. In addition, the amount of elevation travel is sufficient to adjust for drop at extreme long ranges — a mile or more.
Some users will employ the dial-in adjustment just to set an elevation pre-load for a shooting session (more preload for longer range). However, because the M.O.A.B. offers precise 1/4-MOA clicks, you can actually use the M.O.A.B.’s click-wheel to fine-tune elevation settings, just as you might use the elevation turret on your scope. This saves wear and tear on your scope’s internals.
The price for the M.O.A.B. 150 is $399.95. Note: a +300 MOA version is also available for the same price — but we don’t know why anyone would need that much elevation. Made in the USA, the M.O.A.B. 150 (and 300 MOA version) come with a lifetime warranty on materials and craftsmanship.
Editor’s Comment: We are intrigued by this system. We like the idea of external elevation adjustment with 1/4-MOA clicks. However, the precision of such a system is dependent on the fit of the front hinge cross-bolt and the tolerances of the rear rotary riser. With a design like this, if there is any “slop” in the system, you could see a POI change from shot-to-shot. We have NOT tested the M.O.A.B. 150 so we cannot evaluate if the tolerances are up to snuff — this is just something you should consider before shelling out your hard-earned cash.
Bolt-On Version for M1A and M14 Rifles
Cold Shot also offers an adjustable scope base for M1A and M14-platform rifles. This unit has front and rear attachment points for a “no-gunsmithing” installation. Like the standard M.0.A.B. 150 scope base, the M1A/M14 version offers up to +150 MOA elevation travel in 1/4-MOA clicks.
Product Tip from EdLongrange. We welcome reader submissions.
When a scope mounting system costs as much as a factory hunting rifle, it better be something special. At $410.00, the Spuhr Unimount Scope Mounting System is one expensive piece of kit. But if you shoot .338 Lapua Magnums or 50 BMGs, this mount may be worth the money. Made in Sweden, the aluminum Spuhr Unimount integrates “rings” into a +20.6 MOA (6 MIL) base with built-in bubble level. The matte-black-anodized Spuhr Unimount has some interesting design features. The clasping bolts are set at a 45° angle. Ring internal surfaces are grooved for enhanced “grip” (these are not threads — the surface is precision ground and smoothed so there are no sharp edges). Available in 30mm and 34mm diameter (and various heights), the Spuhr Unimount even comes with a scope indexing tool to help you align your scope correctly with the mount. Along with the standard Unimount shown in the photo, a cantilever-sytle Unimount is offered for AR-platform rifles and other guns requiring forward scope placement.
Let’s say you’ve purchased a new scope, and the spec-sheet indicates it is calibrated for quarter-MOA clicks. One MOA is 1.047″ inches at 100 yards, so you figure that’s how far your point of impact (POI) will move with four clicks. Well, unfortunately, you may be wrong. You can’t necessarily rely on what the manufacturer says. Production tolerances being what they are, you should test your scope to determine how much movement it actually delivers with each click of the turret. It may move a quarter-MOA, or maybe a quarter-inch, or maybe something else entirely. (Likewise scopes advertised as having 1/8-MOA clicks may deliver more or less than 1 actual MOA for 8 clicks.)
Reader Lindy explains how to check your clicks: “First, make sure the rifle is not loaded. Take a 40″ or longer carpenter’s ruler, and put a very visible mark (such as the center of an orange Shoot’N’C dot), at 37.7 inches. (On mine, I placed two dots side by side every 5 inches, so I could quickly count the dots.) Mount the ruler vertically (zero at top) exactly 100 yards away, carefully measured.
Place the rifle in a good hold on sandbags or other rest. With your hundred-yard zero on the rifle, using max magnification, carefully aim your center crosshairs at the top of the ruler (zero end-point). Have an assistant crank on 36 (indicated) MOA (i.e. 144 clicks), being careful not to move the rifle. (You really do need a helper, it’s very difficult to keep the rifle motionless if you crank the knobs yourself.) With each click, the reticle will move a bit down toward the bottom of the ruler. Note where the center crosshairs rest when your helper is done clicking. If the scope is accurately calibrated, it should be right at that 37.7 inch mark. If not, record where 144 clicks puts you on the ruler, to figure out what your actual click value is. (Repeat this several times as necessary, to get a “rock-solid”, repeatable value.) You now know, for that scope, how much each click actually moves the reticle at 100 yards–and, of course, that will scale proportionally at longer distances. This optical method is better than shooting, because you don’t have the uncertainly associated with determining a group center.
Using this method, I discovered that my Leupold 6.5-20X50 M1 has click values that are calibrated in what I called ‘Shooter’s MOA’, rather than true MOA. That is to say, 4 clicks moved POI 1.000″, rather than 1.047″ (true MOA). That’s about a 5% error.
I’ve tested bunches of scopes, and lots have click values which are significantly off what the manufacturer has advertised. You can’t rely on printed specifications–each scope is different. Until you check your particular scope, you can’t be sure how much it really moves with each click.
I’ve found the true click value varies not only by manufacturer, but by model and individual unit. My Leupold 3.5-10 M3LR was dead on. So was my U.S.O. SN-3 with an H25 reticle, but other SN-3s have been off, and so is my Leupold 6.5-20X50M1. So, check ‘em all, is my policy.”
From the Expert: “…Very good and important article, especially from a ballistics point of view. If a ballistics program predicts 30 MOA of drop at 1000 yards for example, and you dial 30 MOA on your scope and hit high or low, it’s easy to begin questioning BCs, MVs, and everything else under the sun. In my experience, more than 50% of the time error in trajectory prediction at long range is actually scope adjustment error. For serious long range shooting, the test described in this article is a MUST!” — Bryan Litz, Applied Ballistics for Long-Range Shooting.
Hey Burris, Leupold, Sightron and Weaver — are you reading this? If you want to dominate the market for varmint scopes, give us a large elevation knob offering at least 20 MOA in a single revolution. IOR and U.S. Optics already offer this “one-rev” option on tactical scopes and it is clearly superior when moving back and forth between multiple yardages. Schmidt & Bender offers a single-turn option on some S&B PMII Tactical scopes, along with a color-coded, double-turn elevation turret option.
IOR’s big 9-36×56 scope offers 25 MOA of elevation in ONE ROTATION (and about 75 MOA overall). If you use the zero stop, that one rotation (25 MOA) will get most rifles to 850 yards with ease (and very few varmint shots are made beyond that). That means you should never loose track of your elevation setting. Right in front of your nose is a large visible number that corresponds to your actual come-up: “7” for 7 moa, “12” for 12 moa, and so on. Wow–this is so easy compared to other systems that require multiple revolutions and leave you staring at unlabeled hash marks wondering how many clicks you just dialed in or out.
When this Editor first tried a one-rotation elevation knob I had the same reaction I did years ago when I watched a ultra-high-grade flat screen TV for the first time. Then I thought… “wow, this flat screen is just better in every respect and, eventually, will change everything.” Scopes aren’t TV sets, but I think the large one-rotation knob IS a huge advancement — a breakthrough in scope design. When used with a come-up table showing the elevation needed for various yardages (50-1000 yards), the one-rev system makes it really hard to be “way off” in your elevation. With conventional elevation knobs it is very easy to lose track of clicks (and whole revolutions) as you move up and down to different yardages.
The IOR and U.S. Optics products offering 20+ MOA in one-revolution are large, heavy, expensive scopes. The big elevation knob on the IOR Ultra Long Range scope has about 125 MOA total elevation (25 MOA per turn) with 1/4-MOA clicks. The large flat EREK (Erector Repositioning Elevation Knob) on the U.S. Optics scopes offers 22.5 MOA per revolution, with a total of about 62 MOA in a 5-25 SN-3 model with 1/4-MOA clicks.
Scope-Makers Should Adapt Technology to Varmint Scopes
It’s time for the mainstream scope makers to bring this techology to the market. Adding a one-revolution elevation knob (with 25 moa of travel) to a $600.00 varmint scope would make a huge difference in practical functionality in the field. You could reliably click back and forth between yardages all day long and never lose track of your elevation setting. This is almost as easy as a yardage-calibrated elevation knob (but not limited to a single load.) So, you scope makers out there… How about giving us a one-revolution elevation knob on an affordable hunting scope?
Swarovski has a new 
Leupold has just introduced a new second focal plane reticle with MOA-based hashmarks, allowing precise hold-overs and hold-offs (for wind). The new TS-32X1 reticle, is a minute-of-angle (MOA) based system designed to allow for precision shots without the need for dial adjustments. The TS-32X1 reticle is designed to work with riflescopes that employ 1/4-MOA target adjustments or M1 dials.
Barrett offers an innovative scope ring set that adjusts to two different MOA elevations through the use of variable-position cross-pins in the rear ring. Barrett’s 
“I used [the ExRings] to great effect to win the Australian Long Range F-Class Open competition earlier this year. They enabled me to use a higher magnification scope at the 1200-yard range. I have since bought a second pair and run them on my .375 Cheytac to shoot way out yonder.
Angled Weaver-style or Picatinny-style scope rails elevation “pre-load” are commonplace these days. But most angled scope rails are non-adjustable. 
Reader Lindy explains how to check your clicks: “First, make sure the rifle is not loaded. Take a 40″ or longer carpenter’s ruler, and put a very visible mark (such as the center of an orange Shoot’N’C dot), at 37.7 inches. (On mine, I placed two dots side by side every 5 inches, so I could quickly count the dots.) Mount the ruler vertically (zero at top) exactly 100 yards away, carefully measured.
The IOR and U.S. Optics products offering 20+ MOA in one-revolution are large, heavy, expensive scopes. The big elevation knob on the IOR Ultra Long Range scope has about 125 MOA total elevation (25 MOA per turn) with 1/4-MOA clicks. The large flat EREK (Erector Repositioning Elevation Knob) on the U.S. Optics scopes offers 22.5 MOA per revolution, with a total of about 62 MOA in a 5-25 SN-3 model with 1/4-MOA clicks.
