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.
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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.
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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.
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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?
For months now, we’ve heard rumors of an all-new, high-magnification Nightforce scope, to be introduced in 2012. Unfortunately, Nightforce had no new “super-scope” on display at SHOT 2012, but Nightforce reps did indicate that “important announcements will be forthcoming in a few months”. Possibly we will see the new model(s) at the NRA Annual meeting, but that’s not definite. The only thing we can tell you — and this is NOT official — is that more magnification may be on tap on the high-end, giving Nightforce something to compete with the latest high-magnification competition scopes from other optics-makers.
We were pleased to see that Nightforce is offering an enhanced MOA-marked reticle with 1 MOA stadia (hash marks), and a center floating “X” that is 2 MOA high and 2 MOA wide. This new “MOAR” reticle should be a good choice for long-range shooters who prefer to hold off for windage corrections, rather than dial windage turrets. By comparison, the popular NP-R1 has 1 MOA marks on the elevation bar and 2 MOA marks on the windage bar. With the MOAR you get 1 MOA stadia (dividers) on the horizontal line as well. This should help shooters make more precise wind holds. NOTE: Initially the MOAR reticle will only be available for new NXS 3.5-15, 5.5-22, and 8-32X models (MOAR will NOT be offered in current Benchrest Models). ETA for the first MOAR-equipped NXS scopes is June, 2012.
In the video above, a Nightforce spokesman covers the function of the New Nightforce Velocity Reticle Calculator. This interactive program helps Nightforce scope owners select the particular velocity reticle (from a series of eight available) which best matches the ballistics of their particular rifle and load. Once you input the bullet velocity and BC data for your load, the calculator selects one of the eight velocity reticle options. This gives the scope owner a reticle with vertical hold-over points that closely match the actual trajectory of his ammunition.
Nightforce Adds Workers and Expands Production Facilities
In other Nightforce news, Nightforce Marketing Director Kyle Brown announced that Nightforce is beefing up its workforce and expanding its production facilities. With Nightforce scopes being in such high demand, there have been extended delivery times for some of the most popular Nightforce models. With more assemblers and a larger assembly plant, Nightforce hopes to keep up with growing demand for its products. We commend Nightforce for committing added resources to scope production. This will certainly benefit scope buyers by increasing “on-the-shelf” inventory at Nightforce stocking dealers.
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While we were somewhat disappointed that we didn’t see many all-new precision rifles at Media Day 2012, there were plenty of new riflescopes on display. Among the most impressive new optics were rugged new high-zoom-range, First Focal Plane (FFP) tactical scopes from Hensoldt (Carl Zeiss), Leupold and Trijicon. These new scopes all featured fat tubes, compact overall length, and abundant elevation travel. These lastest top-end FFP tactical scopes offer as much as 26-power in a form factor not much bigger than a “normal” 4-16X scope.
New 3.5-26x50mm Hensoldt Was Outstanding
Hensoldt showcased a very impressive, prototype 3.5-26x56mm FFP tactical scope. Though this scope offers a whopping 7.4X zoom range and 26-power on top, this new Hensold is relatively compact. The reticle in these prototype versions was a very useful (and simple) milradian-based reticle that we hope Hensoldt retains in the production versions. The Hensoldt boasted an impressive 36 Mils of total elevation travel in two (2) turns of the turret. The new Hensoldt still shares the same superior glass and compact size that puts these scopes at the top of their class. We tested a prototype mounted to an Accuracy International AX 338. Expect the production version to be the same size and cost approximately $4000.00.
As you can see in the video, the new Hensoldt coupled with the new Accuracy Int’l AX in 338 Lapua Magnum worked very effectively at 900 meters in some tricky winds. This combination made it fairly easy to break clay pigeons on the bank at 900 meters. Off camera this combination continued to show great accuracy and very effective design features.
New Leupold MK-8
Leupold showed off a brand new MK-8 3.5-25x56mm with a Horus reticle and a beefy main tube. Again, this featured a lot of elevation in one turn as well as a pinch-and-turn locking turrets. This is a big leap forward for Leupold and we feel this will be well-received in the tactical world. Along with the new MK8, we also sampled Leupold’s new MK6 3-18x50mm. This shared similar features as the 3.5-25, and was incredibly compact as well. We expect the MK8 to sell near $4000 and the MK6 to be substantially less, likely under $3000 according to company reps.
Trijicon made a departure from their standard fare and jumped into the tactical scope world with a beefy Front-Focal Plane 3-15x50mm. This featured a well-executed MOA-based reticle and turrets with 30 MOA per turn (a Milrad version offers 10 Mils per turn). The Trijicon showcased the “short and fat” appearance that seems to be the latest design trend in tactical scopes. But though the Trijicon had a fairly short OAL (for its zoom range), it was still quite heavy at 47 ounces. The glass in this prototype version was disappointing for a scope that will retail in the $4K range. Reps told us the production version glass would be much improved. (It had better be, if Trijicon hopes to play in this stratospheric price range.)
It was apparent at Media Day 2012 that scope companies have worked hard to provide more features and more performance in their high-end tactical scopes. Consequently, the latest generation of scopes offer some very interesting and useful innovations — wider zoom range, more compact size, more elevation travel per rotation, and “goof-proof” turret mechanisms. We can only hope that, with more competition in this market, prices may become more reasonable. $4000 is an awful lot of money to pay for a scope.
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Bench-Source, founded by David Dorris, President of Vertex Mfg. Corp., and benchrest shooter Darrell Jones, is now producing precision scope-mounting bases for the Savage round-top Target Action. CNC-machined to exact tolerances from 7075-T6 aircraft aluminum, these bases are extremely light (under two ounces) yet strong. Both Picatinny-style bases and Davidson dovetail bases are offered with either zero taper (flat) or with +20 MOA of built-in elevation. Bench-Source rails also feature precision-cut reliefs to match the loading ports on the Savage Target Actions.
The Picatinny (Weaver) base costs $84.95 (either flat or +20 MOA) while the Davidson dovetail base is just $69.95 (either flat or +20 MOA). This is a good price considering the quality of the materials and machining. (The 7075-T6 aircraft grade aluminum is three times as expensive as the aluminum alloy used by some other rail-makers.) Either style base is available with either a “luster” or polished finish. The price includes a Torx wrench and mounting screws.
Technical Specifications
The Picatinny M1913-A Mounting Rail features 14 symmetrically spaced cross-slots. The base is long enough to mount any popular scope. The Picatinny base is approximately .610″ tall. Parallelism deviates less than .002″ between the dovetail clamping area and top of the receiver after mounting. The screws used are #6-48 x 3/8″ long and holes are drilled and counter-bored to the correct depths. This ensures that users will not damage their barrel threads or encounter interference with the locking lugs when closing the bolt.
The Davidson 1/2″ x 60º Mounting Rail dovetail is parallel over its entire length. The rail is held to very tight tolerances to minimize windage correction (at different ring positions). The Davidson rail should self-center on your action when installed per the included instructions. Both ends of the mount are chamfered slightly on a 30° angle to let the sharp corners of the mating rings align themselves without binding. The 60º dovetails are machined +/- .001″ and measured over two optimum-diameter pins to minimize over-clamping of your rings.
For more information, visit Bench-Source.com or phone: (662) 895-0803.
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Forum member Thomas Haugland (aka “Roe”) from Norway has created an excellent video comparing the features on four long-range scopes: Schmidt & Bender PMII 3-12x50mm, Schmidt & Bender PMII 12-50x56mm, Leupold MK IV, and Zeiss Diavari Victory 6-24x56mm. Thomas shows how the adjustments function, he records the available vertical elevation, and he takes apart the turrets to show how the weather seals work. While the Leupold MK IV has MOA clicks, the three Euro scopes tested by Thomas have mil-based or mil/cm adjustments. These mil-based clicks work well with first focal plane reticles that have mil or half-mil hash marks.
Thomas explains:
These films emphasize the shooter’s Point of View (POV) and ‘user friendliness’. ALL these scopes get the job done, but they have some similarities and differences in the details and your own personal preferences would decide what scope can be labeled ‘best’. The perfect scope doesn’t exist, you’ll have a compromise somewhere — be that economy, magnification, reticle, turret, optical quality, sturdiness…
In these films I’ve set the Schmidt & Bender PMII 3-12×50 as the benchmark for comparison. Not because it is ‘best’ (it isn’t!) but because S&B is one of the manufacturers which first recognized the needs of professional Long Range shooters and put together products [optimized to work well] in high stress environments. The features that are important are: First focal plane, MIL reticles and MIL turrets, plenty of adjustment and suitable magnification.
Note that S&B and Zeiss scopes are also available in the USA with MOA-based turrets and/or second focal plane (SFP) reticles, for those shooters who prefer the MOA system, and SFP. A first focal plane reticle is best for ranging, but a target shooter working at known distances will probably prefer a second focal plane reticle that doesn’t change in size with magnification.
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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.
For months now, we’ve heard rumors of an all-new, high-magnification Nightforce scope, to be introduced in 2012. Unfortunately, Nightforce had no new “super-scope” on display at SHOT 2012, but Nightforce reps did indicate that “important announcements will be forthcoming in a few months”. Possibly we will see the new model(s) at the NRA Annual meeting, but that’s not definite. The only thing we can tell you — and this is NOT official — is that more magnification may be on tap on the high-end, giving Nightforce something to compete with the latest high-magnification competition scopes from other optics-makers.
Trijicon made a departure from their standard fare and jumped into the tactical scope world with a beefy Front-Focal Plane 3-15x50mm. This featured a well-executed MOA-based reticle and turrets with 30 MOA per turn (a Milrad version offers 10 Mils per turn). The Trijicon showcased the “short and fat” appearance that seems to be the latest design trend in tactical scopes. But though the Trijicon had a fairly short OAL (for its zoom range), it was still quite heavy at 47 ounces. The glass in this prototype version was disappointing for a scope that will retail in the $4K range. Reps told us the production version glass would be much improved. (It had better be, if Trijicon hopes to play in this stratospheric price range.)
Technical Specifications
