Category Archives: Optics

Nikon’s P-223 Riflescope And Prostaff 7 Rangefinder

High Performance Tools For The
Hunter And Shooter.

I will admit I have been writing about scopes recently in the “higher priced” bracket. In a large sense they are very esoteric. Most optics sold today are below the $400 range. Many of them are not only useful but also reliable and enjoy very good optical performance. Nikon is among them.

I have not reviewed or evaluated Nikon’s optics in several years. I wish I could keep up with all there is out there now days, but it has become impossible. While doing this review, I brought up their website. They have really had their heads down, working at a fever pitch. I suggest you get the old PC out and take a look. I went through their “Spot On” ballistic software and was amazed at what they have accomplished. You simply enter the cartridge and bullet being used, and out comes the answer. It is available as well on all the new-fangled handhelds as well. I haven’t the real estate to go into it in depth here, but see for yourself. If you are a hunter, this stuff is gold!

The Prostaff 7 Rangefinder works well to 600 yards and gives you the incline angle to the target as well. Here it is shown next to Jacob’s phone, which is quite small as handhelds go nowadays. You can put Prostaff 7 in a pocket for easy carry in the field.

P-223 4-12x40mm

I found myself wishing that I could do a complete review of Nikon’s sporting optics. Unfortunately, that is not possible either. So I will have to stick to the matter at hand. Suffice it to say that this model is also available in 3x32mm and 3-9x40mm.

The P-223 BDC 600 scope has a 1-inch tube, quick ocular adjustment, open turrets, and an open dot reticle with smaller hashmarks between each open dot for elevation hold. It is a progressive reticle. I suppose that is my own terminology, so let me explain. Some reticles have hashmarks on the vertical and horizontal crosshairs that are all spaced evenly. For example, each might be 1 MOA or MIL apart, which I chose to call a static hashmark system. In a progressive hashmark system, each line or circle on the vertical crosshair is farther apart than the last one as you proceed from top to bottom. This is used to simulate the ballistic flight of some particular bullet at some particular velocity.

The reticle in the P-223 was designed around a 55-grain, polymer-tipped bullet with a 3,240 fps velocity. However, don’t think it works for only that bullet. Nikon’s Spot On ballistic software allows you to enter any popular configuration of any manufacturer, case, bullet, etc. The software tells the shooter the range for each dot or hashmark of any of them. It will also allow you to change environmental conditions such as pressure and temperature, and gives you the incline to the target. To get it right, however, you need to use a chronograph to find the true velocity and a rangefinder to get the exact distance to expect a productive hit.

Zeroing the turret is simple and fast. Once in the bull at 100 yards, simply lift the turret, turn it to 100 yards, and then let it back down. From there, the BDC works for both the turret and the dot marks on the reticle.

The reticle is placed in the second focal plane. That has an advantage. Ranges are given for each dot at max power. But since the reticle is in the second focal plane, you can use the Spot On software to find the range each dot will hit at other powers. Using 6X instead of 12X, in this case, greatly extends the distance for each dot.

The fast optical adjustment makes focusing the reticle quick and easy. The power ring is a bit oversized, which makes it easy to manipulate as well. There is no cap on the turrets of this model. If you wish to use the BDC turret, you also don’t want to be slowed down by having to remove a cap. Find the range, turn the dial to that particular range, and fire. For even faster response, use the dots on the reticle. Some scope designers put numbers next to each dot. Nikon has not, which requires you to count down until the correct dot is found.

The scope does not have a parallax/focus turret. The parallax is set for 100 yards. This holds the price of the scope down I suppose. Using this scope for its intended purpose to a mid-range maximum, it should not present a problem. Holding for wind is a problem, but it is in any case. Let me explain: Suppose the target has been ranged at exactly 600 yards. You simply put the 600-yard dot on the target. Now you have to estimate the wind over that entire distance. Suppose further that you estimate the wind to be 10 mph from right to left. You put the dot on the target and then must move the dot some distance to the right into the wind. How far over do you move? It is the same problem you have with a plain crosshair when holding above the target for elevation. Without the dots, how far above the target do you hold? You are aiming in space. This is exactly what brought about the Christmas tree reticle with wind dots at 5, 10, 15 mph and so on. But even if you make the correct guess for hold off for a 10 mph wind, it may be going the opposite direction at 300 yards. Wind will always be more problematic than elevation.

Image quality of the P-223 is very good. Resolution is good, contrast is good, and I could not detect any aberrations. Color balance is very good with no bleeding or fringing. It is also fully multicoated. The scope is made in the Philippines, but I still wonder how they can produce this kind of quality and market it at such an affordable price.

The Nikon P-223 4-12x40mm BDC 600 has a 1-inch tube. The dials are not capped, making for fast adjustments in the field. The ocular adjustment is the quick adjust type as well. The power dial is also large, making power changes easy as well. The optics are very good.

The Bullet Drop Compensator is made specifically for the .223, particularly a 55-grain polymer tipped bullet at 3,240 fps. Turret clicks are 1/4 inch at 100 yards. Once zeroed, simply lift the turret, move it to 100, and you are done. From there, the turret is moved to the proper yardage for the hit.

Prostaff 7 Rangefinder

This fellow harbors a lot in a small package. I have one of the smaller hand-held phones on the market and the Prostaff is not much larger than it. Another advantage of the unit, although it might be just a personal opinion, is the black display. I can see the crosshair, the range, and the angle against any background, something often a problem with the red displays, even those that allow you to change brightness. This poses even a larger problem for some who are colorblind. But the unit has LED illumination that can be turned on, enabling you to see the crosshair in poor lighting conditions. Another useful mode allows the unit to give the distance to the intended target when a closer object like brush might be between you and the farther priority target.

The unit also includes the incline angle to the target. The literature deems the Prostaff 7 as a 600-yard unit, and it lives up to the literature. If you’re shooting at a 30-degree incline to that range, it behooves you to know the incline or you’ll likely miss the target high.

When I first started evaluating optics nearly 30 years ago, I did quite a bit of work with Nikon’s products. I remember making the statement I had never met a Nikon I didn’t like. These two products have not changed my mind. Used together, they will do a good job for most hunters at medium ranges.
By Jacob Gottfredson

P-223 4-12×40
Matte BDC 600

Maker: Nikon Inc.
1300 Walt Whitman Rd.
Melville, NY 11747
(631) 547-4200
www.gunsmagazine.com/nikon

Magnification: 4X-12X
Objective diameter: 40mm
Tube Diameter: 1″
Eye Relief: 3.7″
Weight: 17.5 ounces
Click Value: 1/4″
Length: 14.1″
Internal Adj. Range: 60 MOA elevation & windage
Reticle: BDC 600
Price: $249.95

Prostaff 7 Rangefinder
Maker: Nikon Inc.

1300 Walt Whitman Rd.
Melville, NY 11747
(631) 547-4200
www.gunsmagazine.com/nikon

Measurement Range: 5 to 600 yards
Increment: 0.1 yard
Magnification: 6X
Eye Relief: 18.3mm
Operating Temp: +14 degrees F to +122 F
Power Source: CR2 Lithium battery
Weight: 6.17 ounces
Beam Divergence (MRAD): 1.8 Vertical: 0.25 Horizontal
Price: $299.95

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GUNS October 2013

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Long-Range-Finding And More

Gunwerks G7-BR2 Solves Many problems.

Apart from those issued to the military, most rangefinders are about the same. They give you the range, some better than others. Lately, they have shown the incline angle to the target. Then came the generation giving the come-ups in MOA or MILs or a BDC readout, along with the change needed at inclined angles. These were made possible by using pre-programed bullet-flight patterns that might fit yours or might not. All has changed with the introduction of the G7-BR2.

I have used many of the rangefinder models on the market since they were introduced. They were a boon to the hunter and to military users. Knowing the exact range to a target changed the game dramatically. Contrast the old method of trying to judge both the depth of the target and how much it covered between hashmarks. Still, you needed to know the come-ups or the holdover once the range was found. That meant referring to a table or a smart phone with a ballistics app. Lastly, you could just hold over some amount by feel, and let ’er rip!

Some riflescopes, such as some made by Zeiss, gave the range, and then supplied a red dot to indicate the holdover. Just put the red dot on the target and fire. You were still held to certain pre-programmed trajectory flights. Again, it might match yours or it might not.

What is needed is a rangefinder that allows you to program in the exact trajectory flight of your bullet—one in which you can program any bullet’s ballistic coefficient, muzzle velocity, sight height, etc. And one that will also monitor the environmental conditions as well as calculate the incline angle and change the come-ups accordingly. The folks from Gunwerks now provide one that does it all.

I have no idea how they packed so much in such a small unit, but they did. Some simple programing is required by the user accomplished using the four buttons on top of the unit. In use, however, just one push with the “fire” button gives all the information needed for the shot. It will also give you the hold off for wind as long as you know what the wind speed is. Wind hold off is accomplished by monitoring temperature, barometric pressure, angle, and then giving the shooter the wind hold in 5, 10 and 15 mph increments. It is the shooter’s job, however, to decide what the wind speed and vector are.

The owner’s manual states the ballistic calculations are good to 1,400 yards. The manual also states that the unit is good from 32 degrees F to 122 F. I contacted Aaron Davidson of Gunwerks about that. After all, the majority of hunting takes place in the fall and winter. The temperature is often much below 32 F. It seems the unit still works, but the display may respond more slowly.

In the range-only mode, the G7-BR2 gives the line-of-sight distance to the target, the approximate altitude, barometric pressure, temperature, and incline. They have coupled this with some innovative ballistic software for long-range shooting. The Gunwerks website is a wealth of information and long-range shooting videos.

The shooter wants to know not only the distance to the target, but the hold over. The G7 does this in a couple of modes: A ballistic turret (BDC) or MOA. The G7 will accept five different cartridge profiles. After choosing a profile, you enter the method to be used, the drag coefficient, ballistic coefficient, muzzle velocity, sight height, and zero range. If you’re using a ballistic turret, the current temperature and altitude are also entered. Thus, rather than trying to get close to some ballistic flight range, the G7 programs in the exact data of your round! The G7 then monitors the temperature, altitude, and incline and changes the holdover accordingly.

The G7 is a real breakthrough for the sportsman. Granted, you can use several means to gather the data to make shots at mid to long range, but it is time consuming. A first-rate range finder is needed along with a ballistic program residing on a handheld computer of some sort. An instrument such as a Kestrel is needed to monitor temperature and barometric pressure. Lastly, inclinometer giving the incline angle to the target is required. You read the distance to the target, note the angle, and then monitor the temperature and barometric pressure with the Kestrel. You then enter the distance, angle, temperature, and pressure into the handheld computer and ask for results.

The handheld computer gives you the MOA to dial, and the shot is taken. But the G7 monitors all that data once the button is pushed and gives the shooter the MOA to dial immediately. It knows the angle, the temperature, and the barometric pressure and calculates the MOA to dial according to those environmental conditions. No more need for a handheld computer, or a chart, or the Kestrel (except to estimate the wind).

Still, it is not quite that simple. The first problem is ranging. It takes some experience and a steady hold to get an exact range. And an exact range is necessary to place a productive shot on a target. Even the best rangefinders have a dispersion angle that often registers objects possibly in front of or behind the target. If the wrong distance is used to hit a target, even a small miscalculation will result in a miss or an unproductive shot. Shots at mid to long range take considerable practice and experience, and any significant wind, wind change at different ranges, or a switching wind will foil the entire enterprise. Ultra long-range is even more difficult. Know your limitations!

Mirage is extremely helpful in gauging wind near the target or between the target and the muzzle. But remember—mirage bends light. It may be the target you are aiming it is only a phantom, and the real target lies either to the right or the left of what you see by some small amount.

If the G7 calculates “lift,” “spin drift” and “coriolis force,” they are not mentioned in the manual. All of those forces must be reckoned with to hit ultra-long range shots. Briefly, wind moves the bullet in the direction of the wind, but lift will also move the bullet up some amount in a right-to-left wind and down some small amount in a left-to-right wind as well. Spindrift will move the bullet to the right some amount in a right-hand twist barrel. Coriolis force will move the bullet some amount as well depending on the direction of the shot and in which hemisphere it is taken. At mid-range (300 to 600 yards) and long range (600 to 1,000 yards), these affects are not large relative to targets about 20 inches square. But, along with wind, they become even more troublesome at ultra-long range.

The G7 is a 7X monocular. At the rear of the unit, just between the ocular lens and the body, there is a small, knurled ring. It is used to focus the optic. I found the glass to be very good. Resolution and contrast are good. It focuses well to the edges. I could detect no aberrations.

Among its other features, the display is bright enough to read on any background, an important requirement where many other rangefinders fail. But those who are colorblind might still have difficulty.

Bottom line: The G7-BR2 offers a tremendous advantage to the hunter who wants to extend the range beyond the traditional limits of 200 to 300 yards. It offers the entire data set required to make shots at mid to long range that, so far as I know, is not available elsewhere to the civilian shooter. It comes with battery, owner’s manual (both paper and CD), and all is included in a semi-hard case.
By Jacob Gottfredson

G7-BR2
Maker: Gunwerks
P.O. Box 22, Burlington, WY 82411
(307) 762-3240
www.gunsmagazine.com/gunwerks
Dimensions: 2.10″ x 4.45″ x 5.09″
Magnification: 7X
Weight: 14.3 ounces
Functional Range: 1,500 yards
Max Range: 2,000 yards
Max Ballistic Compensation: 1,400 yards
Min Temp for Ballistics: 32 F
Max Temp for Ballistics: 122 F
Beam Divergence: 2×4 Mrad
Target Modes: Near, far, continuous,
Display Backlight: LED
Battery: CR 123
Accessories: Case, neck strap
Price: $1,599

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A Cadillac Among Tactical Optics

Leupold M8 1.1-8x24mm CQBSS.

So this guy calls and asks me what optic he should buy. He wants a scope to perform at close quarter but also allow him to shoot mid-range. I mentioned several. His comments were those scopes did not go low enough; the other scopes did not go high enough. His comments were true for what he wanted until Leupold hit the market with one of the most innovative scopes in many years.

The initials in Leupold’s Mark 8, 1.1-8x24mm CQBSS stand for Close Quarter Battle Sniper Scope. With a 1.1- to 8-power ratio, it makes what the guy wanted possible. Leupold also put the reticle in the first focal plane. The result is a reticle, like the M-TMR and H-27D that can be extremely useful for quick shots at mid-range on 8X. But when turned to 1.1X, the center ring becomes like a red dot reflex sight when the illumination is turned on. The 34mm main tube allows a huge elevation and windage range if you prefer to dial or hashmarks if you prefer not to.

The innovation does not stop there. They have designed a dial system unique, useful, and reliable. Most tactical scopes use dials without caps. I have more than once suspected my elevation settings got moved while carrying the rifle on my front or back. Caps, however, are too slow to deal with in a tactical situation. Leupold has solved that problem by designing squeeze-top dials. Under normal circumstances, the dial can’t be moved. But when quick dial changes are required, simply squeeze the top and move the dial. Release and it locks where you left it. But what happens in a dirty, sandy environment? Some say it makes the squeeze top useless. Others say they have not had a problem. However, if it did happen, shooters can use the hashmarks on the reticle.

In explaining the high tariff of this scope, Leupold explains the aspherical lenses and very high quality components drive the cost, and the 1.1X to 8X zoom is no easy animal to deal with either. The H-27D reticle adds the better part of a grand over the standard mil dot. Just holding and looking at the scope gives you the immediate impression of quality stuff.

Many modern scope companies market their reticles as good for a specific bullet, velocity, and ballistic coefficient. This normally denotes what I call a progressive reticle system. That is, the subtension between each hashmark on the vertical reticle increases. This in theory matches some range of bullet, velocity, and ballistic coefficient range. Neither the H-27D’s nor the M-TMR’s reticles are progressive, which is OK with me as I prefer a reticle with hashmarks that subtend the same distance for every mark. It makes ranging and holdover easier. But Leupold has made them specific for the 5.56mm and the 7.62mm with the use of BDC dials.

The truth is, both systems will work just fine with any bullet, any ballistic path, at any velocity, however, ranging becomes a bit more problematic with a progressive hashmark reticle.

The illumination turret is on the left side of the manifold. Many scopes require the user to turn the dial completely around to access the brightest illumination, while others do the opposite. The MK8 can be turned in either direction, making the best illumination quicker to access.

Turning the knob on the left gives you eight levels of brightness. But that solves another problem as well, that of very close quarter shots, made possible by placing the reticle in the first focal plane. As you know, subtention between the lines is then proportional to the range at all powers. This makes ranging the same at any distance but also solves the other problem of close shots. That is, when turned to 1.1X, and with illumination on, it acts as a close quarter reflex sight.

Image quality is excellent, and at this price point, you expect no less. Resolution is sharp, contrast excellent, and I could not detect any aberrations. Color balance is very good with no bleeding or fringing. I suspect that the ark seconds are very low.

optics 1

The illumination turret is located on the left side of the manifold (above) and can be set so either high or low illumination can be accessed first. Markings on the turrets are clear and precise. The elevation and windage turrets will not move during carry, but are easily changed by squeezing the turret and rotating (below). Since turret caps restrict quick access to the turrets, and exposed turrets can be spun without being noticed, the squeeze turrets solve both problems. A zero stop is included with the use of a nut at the bottom of the turret.

optics2

Testing

I mounted the MK8 CQBSS on a LaRue upper and DPMS lower and sighted it in at 100 yards. I found the squeeze dials took a little getting used to. I also found the glass to be unusual. Not bad, just different as I changed from 1.1X to 8X. An 8X power ratio must take a bit of trickery in the guts of the scope, requiring a strange method of moving lenses from 1.1X to 8X. However, it was obvious high-quality glass is used.

This scope allows you to either dial up to distance and right or left for windage or use the reticle to both range and for holdover and windage. Since the scope’s primary purpose for speed is centered on the use of the hashmarks, I turned to mid-range, chose the appropriate hashmark, and started pulling the trigger at distances of 200 to 600 yards. Nothing but resounding hits on metal at each range. But the same result happened with the BDC. Luckily, I live at sea level, temperature approximately 60 degrees F, pressure approximately 29.53 Hg, and I was shooting the AA53 MK262 Mod 1 5.56mm round.

The M-TMR is a Mil-Dot reticle. Ranging with it takes a bit of math. Holdover does as well. The BDC turrets make it easier, and it is a real advantage to have a reticle built specifically for your cartridge. In this case it is for the 5.56mm and the 7.62mm military cartridges. This is also predicated on standard conditions at sea level. Put the 600-yard dot on the 600-yard target and voilà! Problematically, not everyone lives at sea level or has a 20-inch barrel and might not even like shooting military-style bullets. The result is the 600-yard dot might not hit the 600-yard bull. But don’t worry, you can use any cartridge, bullet, velocity, ballistic coefficient, or conditions you desire and make the reticle work perfectly with the use of any modern ballistic software.
By Jacob Gottfredson

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M8 CQBSS
Maker: Leupold
14400 N.W. Greenbrier Pkwy.
Beaverton, OR 97006
(800) 538-7653
www.gunsmagazine.com/leupold

Actual Magnification: 1.1X-8X, Length: 11.75″, Tube Diameter 35mm, Eye Relief: 3.7″ (1X), 3.3″ (8X) , Weight: 23.2 ounces, Elevation Adj. Range: 100 MOA, Windage Adj. Range: 150 MOA, Illumination Power: 2032 Lithium 3V,
Price: $4,999.99 (H-27D: $5,749.99)

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Point-Of-Impact Shift

Benchrest competition offers some scope innovations other precision shooters may apply.

Do riflescopes shift point-of-impact and for what reasons? They are notorious for doing so, but how much matters? That depends on what you are trying to do with it, i.e. what level of accuracy and precision you require. If it is great enough, it can affect any shooting endeavor.

I have been competing in several shooting genres my entire adult life. None are so demanding of precision than 100-, 200- and 300-yard Benchrest. If, on a good day, you are not shooting 25-round aggregates in the teens, you are not competitive. If your scope shifts point-of-impact for any reason, you will end up in the bottom half or worse at the end of the match. The scopes used for many years were the 36X fixed-power variety made particularly for Benchrest. Shooters began to suspect that point-of-impact (POI) shift might be the reason they were not doing as well as they thought or hoped they should be.

In the mid-’90s, Cecil Tucker from Odessa, Texas, began working on the problem. He found the erector tube was supported against the elevation and windage turrets by weak leaf springs positioned opposite the turrets. They exerted about 7 pounds force on the erector tube but did not push the erector tube back to battery efficiently. He also found the method used to secure the erector tube axially was inefficient as well. Those scopes also used an adjustable objective to adjust parallax that sometimes did not move as intended.

He set about trying to correct these problems. He first removed the leaf springs. He then drilled a hole in the side of the scope body 120 degrees from the elevation and windage turrets. He placed a strong spring that exerted approximately 30 pounds of pressure against the erector tube to keep it in place. He also added a wave washer at the end of the erector tube to support it axially. The spring on the side of the scope was housed in a cylindrical tube, attached to the side of the scope. The strong spring supposedly ensured the erector tube was always held tightly against the turrets, hopefully preventing POI shift.

optics 1

The internals of this scope have been modified and hard supported inside, the internal adjustments have been removed, and the adjustments transferred to an external mount. The device is shown on the left side. The owner, Gene Bukys, wins most of the matches he attends. Is this the reason?

A few years later Burris incorporated that idea in their scopes, calling it the Posi Lok. Burris added another twist. You could leave the spring to act just as Cecil’s did, or the cylindrical piece on the outside of the scope could be screwed in until the erector tube could be held firmly in place. To change sight-in, you had to unscrew the cylindrical piece, make the adjustment, and then screw it in again, or just use the strong spring.

A few years after that, other ambitious and innovative shooters began taking scopes apart, understanding their mechanisms, and securing the internal parts to alleviate the problem. They were not satisfied with holding the erector tube in place with a strong spring alone. They also wanted to ensure the erector tube could not move in any direction and neither could the lenses. But this presented another problem: How were they going to change sight-in. The problem with the old mounts like those used on Unertl external adjustment scopes is the adjustments rode on the outside of the scope tube. These were not reliable either because the contact points wore uneven slots in the scope body.

Probably the premier innovator is Gene Bukys. Besides securing the internals, he designed a mount that will move the scope for sight-in without anything touching the scope body. Did he succeed? No way of telling, but his performance might suggest he did. He wins most of the matches he attends, to include the National and World Championships. Could he have done it otherwise? Who knows? But one thing is certain, it has not hurt him.

Another innovative top flight Benchrest shooter was fixing scopes at a slight cost by inserting a plastic cylinder in the side of the scope tube to hold the erector tube in place.

All this caused some scope manufactures to look closely at the problem and begin to eliminate the problem of POI shift. The March scope was one such endeavor. That scope will be the subject of another article.

I will admit Benchrest is a very esoteric endeavor, and few riflemen expect teen aggs from their rifles. But there are times when POI shift can ruin a hunt or some other competitive sport. On two occasions I have slipped on a mountain side and taken a very bad fall. In both cases, the scope ended up between me and a rock during the fall. In one case, the tube body was badly dented. In another, I could not see that the scope had been harmed. But in both cases I checked it anyway, and, in both cases, the sight-in was off both vertically and horizontally, significantly enough to have missed any animal I might have shot at. One of them ended up 16 inches high and 12 inches left at 100 yards.

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Bukys scope and mount shown from the right side. Note the turrets have been removed. The external adjustments do not ride on the scope body or transfer any stresses from the rings to the scope body like the old external adjusting posi mounts.

If you suspect unexplained, errant shots might be from a scope with POI shift, there are a couple of things you can do. Devise a method to hold the rifle down on bags so it does not move. Aim at a target and dial the turrets. If one or both do not respond or responds by jumping around, you probably have a bad or broken leaf spring or one that has moved out of position. I had it happen once. I sent the scope back. It was repaired with a note attached that said one of the leaf springs had not been heat-treated and had broken. Which brings up the second option. Just send the scope back to the manufacturer and tell them the scope will not hold point-of-impact. Many will replace the scope or the internals if that is the problem.

Some people, including some writers, like to box a scope. That is, shoot at a point, dial the turrets up some arbitrary amount, then right, then down, and then left back to the beginning point and see if that shot goes in or near the same hole. Really enthused boxers go around the box several times to see if the dials are repeatable. Others wonder if the dials really give them 1/4-inch moves per click, or even if some clicks do and some don’t. Of course that might be MOA, centimeters, MILS or whatever. The process of boxing with live ammo might tell you if the movement is reliable under recoil, but it can be done without shooting as well. Hold the rifle down, put the crosshair on an intersection on a grid, then move up, right, down, and then left. Determine if the crosshair moves as advertised and reliably. I did on a suspected scope and found out immediately that the windage turret was not moving the crosshair at all or in jumps.

A scope manufacturer at a writer’s conference once said the average, reliable life of a hunting scope was 3,000 rounds. After that you could expect POI shift and other problems. For the average hunter, that might mean a lifetime of shooting. For others, that would mean less than a year. Most benchrest shooters have found that premium match-grade barrels are good for about 2,000 rounds using 6mm PPC ammo. At some point, a shooter is going to be frustrated by either his scope or his barrel and wonder which is the primary culprit.

optics

A newer rendition of the old posi mounts. This arrangement is frequently used by very long-range varmint hunters, although the rear mount would be extremely high. Sight-in changes are made by turning the micrometer dials for both elevation and windage. However, extreme sight-in changes may put stress on the scope body through the ring. Also, where the micrometer touches the scope body, a wear point may begin to form.
By Jacob Gottfredson

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GUNS April 2013

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Easier Holdover Hits

The Zeiss Conquest 4.5-14x50mm MC Riflescope.

Zeiss’ American Conquest riflescopes represent a good bargain for varminters, hunters, and competitors. Almost half the price of their European models, but primarily produced with 1″ instead of 30mm main tubes and 1/4″ clicks, they retain most of the engineering found in the more expensive Victory series. While the glass produced for Zeiss’ Conquest and Victory optics are free of arsenic and lead, their proprietary Advanced Optics System (AOS) allows them to cut the glass thinner, thereby reducing weight, and is so far used exclusively in their Victory series. The glass in the Victory series is also designed to slightly enhance color rendition and clarity over the Conquest. But the Victory costs considerably more as well.

opitcs 1

The Conquest 4.5-14x50mm scope can be ordered in stainless finish (shown) or matte black.

The move to holdover hash marks and ranging reticle designs has forced nearly every riflescope manufacturer to come up with innovative designs that lend a significant amount of flexibility to riflescopes. Not to be outdone, Zeiss enlisted the genius of two well-known American innovators, Mickey Fowler and Gerald Perry. Holdover systems are certainly not new, and creative ways to approach the opportunity surface every year. Simple is good. On the other hand, simple does not always solve all the opportunities you might like to take advantage of.

The old Mil-Dot system, for example, is simple but sometimes a bit difficult to learn. Some reticles go to the other extreme, making the image look like a Venetian blind. Neither is bad, and some users who practice often accomplish phenomenal things with them.

For the average shooter, a system that accomplishes his needs in a simple to understand and apply way, who has not the time to practice weekly or possibly even monthly, the reticle system must work the way he thinks. It has to be intuitive. As an engineer, I have seen the rise of sophisticated computer software replace the old “by hand” method to accomplish the mathematics required to solve problems requiring billions of calculations. Some of them arrive at my office with manuals that would intimidate Einstein (Well… maybe not). But some are completely intuitive and use input data the way engineers were taught to think. The manual often sets on the shelf, gathering dust as the user completes design after design.

In my humble opinion, the same should hold true for shooters. The progress taking us far beyond the old plex reticle is as much a boon for the shooter as computer software is for the engineer. Thirty years ago, the engineer had to make many conservative assumptions in two dimensions to complete a design.

It would take him months of calculations. Once done there simply was not time to look at five or six alternatives or even one more, searching for the best and most economic solution. Today, the same problems are completed in three dimensions without conservative assumptions and done so in milliseconds. Alternatives can be explored and exhausted, looking for the best and least expensive design, all the while taking much less time than the old methods.

This same technology is now available for designing optics and interior and exterior ballistics, making it fast and simple for the shooter to obtain data he can be use in the field. Now the shooter need not make mathematical calculations in the field, hold over the target in space in some empty quadrant of the image, use guess work, or even carry data cards.

The Zeiss reticles were designed by Mickey Fowler. Mickey is a legendary pistol shooter, and in his day won several national championships and Bianchi titles. But it was his love for hunting coyotes that brought about the search for a reticle to meet his needs. Those critters don’t often stand still, nervously running or trotting, stopping, trotting again, giving the hunter only seconds each time to range, select the correct holdover or dial to range, and fire.

Working through several generations of reticles, Mickey hit on reticle designs that do the job for coyotes or any hunting situation. Mickey, in collaboration with Zeiss, then worked out the Rapid-Z reticle styles, thickness, etc., exclusively for Zeiss.

I spent several weeks evaluating the Conquest 4.5-14x50mm with the Rapid-Z 800 and 1,000 reticles. The scope has great potential in the field with the new reticles, and the glass is excellent. For an antelope, coyote, varmint, or a deer and elk hunter in the Rocky Mountains, shots are often past 250 yards. The scope has 68″ of travel for dialing the correct comeups for a long-range shot, but its potential was realized with the addition of Mickey’s reticle and Perry-System’s software.

optics 3

Zeiss retains the European-style quick diopter focus (above). The turrets are designed
like most target-style dials with 1/4″ clicks and an even 10-MOA revolutions. A side
parallax adjustment (below) is standard with this scope. The dials are reset to zero
after sighting in by loosening the screw shown in the top of the elevation dial. Oddly,
the dials turn opposite of most scopes. They are available in a hunting turret as well.

optics 2

The new reticles turn the Zeiss Conquest and Victory riflescopes and the Diarange into superb hunting glass. But the innovation does not stop there. With the use of online software from Perry-Systems’ on the Zeiss website, the shooter can configure the scope’s reticle to fit any cartridge’s ballistic path, optimizing the use of the reticle. Perry-Systems has incorporated the Rapid-Z reticles into their software as well if you prefer more in-depth analysis.

The concept of the reticle is not new. Many manufacturers and designers are using hash marks both below and above the center crosshair for holdover. But the Zeiss Rapid-Z reticle design lends itself to the way shooters think. For example, horizontal wind bars and dots are positioned to account for mile per hour wind increments. To gain an understanding of that, consider the Mil Dots used by the military. The spotter thinks of wind in miles per hour but then must translate that into the number of Mil-Dots required to hit the target. Using the Zeiss Rapid-Z reticle, the dots are already positioned for wind drift in miles per hour, not requiring the additional time for translation.

The same thinking applies to the vertical holdover bars. The reticle is positioned in the second focal plane. The software allows the shooter to determine what power on a variable scope best fits his cartridge’s ballistic path to match the numbers on the reticle’s vertical crosshair. The reticles are designed for varmints, big game, and long range. However, the user can simply use the highest power, and the program will tell him what ranges the hash marks are good for. As a fall back, the reticle is also designed for precision ranging. The ends of the crosshair have incremental hash marks, the tips of which are further broken down. Unlike Mil Dots and most other hash marks reticles, this gives the shooter the ability to more precisely determine the range to a target, given that he knows something about the target’s size and has a steady rest.

Using the Conquest series of riflescopes, the shooter ranges the target, preferably with an adequate rangefinder. Knowing which hash mark gives the correct holdover allows the shooter to make the hit. The reticle makes this easy because each hash mark is numbered. Once the shooter has determined his bullet’s ballistic flight path, and selected the correct power, the numbers correspond to the range. With the new reticle and the Diarange Integrated Rangefinder scope, he now ranges the animal, transitions to the red dot and fires, never having taken his eyes off the animal. And he did it all in only seconds. Using the Conquest series of riflescopes, the shooter ranges the target with an external rangefinder or the hash marks and then uses the correct hash mark for holdover. This slows the acquisition for a hit, but a Conquest scope and an external range finder cost considerably less than the Diarange.

If you use the software to optimize the power setting, the ballistic path will correspond to the hash mark numbers. For example, on the Rapid-Z 800 reticle, the numbers are 1 through 8, meaning 100 through 800 yards. The software tells you where to sight in on the main crosshair and what power sitting to use so the bullet’s flight path corresponds to those yardages or very closely so. For example, instead of using the highest power of 14X, the shooter may set the power ring on 10X. Alternatively, the shooter can leave the power setting on 14, and the software will tell the user what each hash mark corresponds to what range. The hash marks are further divided. So, for example, if the target is at 525 yards, the smaller hash mark 1/4 between 500 and 600 would be used.

Enter Zeiss’ website and access the Rapid Z calculator. Choose your cartridge, bullet, velocity, etc. Now watch what happens when you change the power setting of the reticle and scope you chose. At some power setting, the hash marks will be close to 100-yard increments that mirror the hash mark numbers 2, 3, 4, etc. But as I pointed out earlier, you can use the full power and then make a chart that tells you what yardage each hash mark represents. Alternatively, you can use the dial to range as well.

The Conquest series of scopes range from 3-9x40mm to a 6.5-20x50mm. The Victory, the Conquest, and the Diarange scopes and binoculars continue to employ only top-quality glass, materials, and manufacturing. They are fully multi coated on all air to glass surfaces, waterproof in compliance with ISO 9022-8, and come with a lifetime transferable warranty. The grinding and coatings on the lenses are still some of the finest in the world. They are among the most aberration free lenses money can buy.

optics 6

The Rapid-Z 600 meets the needs of most hunters using cartridges normally
producing enough energy to down big game at ranges out to 600 yards. Zeiss
has suggested cartridges on their website that are optimized to each reticle and
for which the reticles were designed. However, any Rapid-Z reticle can be
used and optimized for any cartridge.
By Jacob Gottfredson

Conquest 4.5-14×50 MC
Maker: Carl Zeiss Optics, LLC
13005 N. Kingston Ave.
Chester, VA 23836
(800) 441-3005
www.gunsmagazine.com/zeiss
Magnification: 4.5-14x50mm, Tube diameter: 1″, Eye Relief: 3.8″, Elevation Adjustment: 68″ at 100 yards, Windage Adjustment: 45″ at 100 yards, Click Adjustment: 1/4″, Parallax: 30 yards to infinity, Reticle in Image Plane: 2nd, Length: 14.02″, Weight: 19.75 ounces, Price: $1,055.54

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Pride-Fowler’s CQB Riflescopes

Making hits quickly at many ranges.

The hills are alive with close quarter battle scopes. A trip on the Internet reveals we are drowning in them. It is interesting to note the many differences. While most do the same thing, the people writing the specs manage to make them slightly different, particularly the reticle. Are they useful? I tend to think those from Pride-Fowler Industries (PFI) are.

For a particular and varied purpose, I have several impossible demands in a scope. It must have a reflex sighting system that allows shots at very close range. It must have the ability to sight and hit targets from 0 to 600 yards. It must have the ability to range. It must have a means of adjustment for wind. It must have illumination. And it must have the ability to do all this without using the elevation and windage turrets. PFI offers exactly that in their RR-CQLR-1 1-4x24mm.

How PFI managed to do all that is an American exercise in innovation. The more I use the scope, the more I am impressed by their thinking. They started with their now well-known Rapid Ranging System, which is currently being used by Zeiss as well. Lines, which I commonly call hashmarks or bars, are spaced below the main, horizontal crosshair. They are progressive subtention lines spaced in a pattern to accommodate the ballistic path of the .223, .308 and other cartridges matching those ballistics at specific velocity ranges. That is a marketing strategy I have some difficulty with. While it appeals to many, it may be a turn off to anyone using a different ballistic path and velocity. The truth is: the system will work just fine with any ballistic path at any velocity. I don’t have the real estate in this article to explain that, but trust me.
By Jacob Gottfredson

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Parallax And Distortion

How to adjust your scope.

I have written about parallax on several occasions in this magazine. Yet, questions still arise, partly because users are seeing other distortions that sometimes make adjusting for parallax confusing. Recognizing these distortions as not belonging to parallax might make the exercise less frustrating.

Parallax is normally described as the image cone entering the objective lens not converging at the reticle. Webster defines parallax as, “An apparent change in the direction of an object, caused by a change in the observational position that provides a new line of sight.” A riflescope may be parallax free at one distance and not another. Riflescopes that have no parallax adjustment are normally set at some range at the factory. It might be at 100 yards or some slightly longer distance. If the riflescope includes a parallax adjustment, you can fiddle with the knob or the front adjusting objective until it is parallax free at any distance desired.

The internal cone of convergence from the objective lens becomes shorter or longer as the image moves closer or farther away. Stated differently, the internal cone is not the same length for images at different distances.

Optics

The observer is viewing through the ocular lens from an angled position (above).
Note the position of the crosshair. Also note that there is no color fringing at the
edges of the white board on the black backer. One sign of a superior optic
(a Zeiss ranging riflescope, by the way). Now the observer is looking through
the ocular lens, straight on, with a full view (below). Note the position of the
crosshair is in the exact same spot. The reticle is parallax free at 600 yards.
If it were not, the position of the crosshair would have moved about 1/2
(or more) the width of the white board from one photo to the next.
The telephone post to the left of the target is old and is leaning. However,
from one photo to the next there is no pincushion or barrel distortion.
Note the clarity when the eye is centered (below).

Optics

Not A Rangefinder

Some refer to the parallax adjustment knob as the focus knob. In fact some people try to use it for ranging. As an example, suppose a deer is located exactly 600-yards away. You turn the parallax adjustment knob until the deer is perfectly focused and is parallax free and then look at the numbers on the knob. You would expect to see the knob positioned at exactly 600 yards. Voilà! Just dial in your 600-yard dope and have at it. Although that seems perfectly logical, unfortunately, it does not always work that way for several reasons.

Some optical designers and manufactures do an excellent job of securing the objective lens as well as ensuring that moving parts move exactly and then labeling the parallax adjustment knob with great precision. Others, well, not so much. Even so, heat and humidity tend to play games with those dimensions. During competition, it is common to have to tweak the parallax a bit throughout the day. As you might now imagine, some scopes are perfectly parallax free and focused well at 600 yards, but a look at the parallax adjustment knob says almost 700 yards or maybe close to 500 yards. To rely on that for ranging could mean missing the shot.

It also depends on the manufacturer’s method of adjusting parallax. Some do it by adjusting the objective lens, others by a knob located on the left side of the elevation and windage manifold. Some actually use a portion of the ocular housing. On many European style “fast focusing” ocular diopter adjustments, it must be tweaked a bit to obtain the best focus when the image appears to be parallax free. On occasion, you will find a scope where the image is still a bit fuzzy when it is parallax free, or some small amount of parallax when it is perfectly focused. Such situations can drive you nuts.

On occasion, that will be complicated by another phenomenon. There is a small amount of distortion at the edge of the field in most scopes, sometimes referred to as vignetting. Generally, in any riflescope, distortion and field curvature are greater at lower powers. Trimming the field of view would reduce this effect, but that consequence is not considered acceptable since the purpose of lower power is generally to increase field of view.

Another phenomenon is related to field curvature or Petzval curvature. With this condition the image of the target at the reticle is actually curved like a shallow bowl. There are two components of field curvature, horizontal and vertical, where the field may actually curve slightly more in one axis than the other. During the optical design, the designer has the flexibility to minimize field curvature, and also the ability to place more emphasis on the horizontal or vertical components. However, as with any optical aberration, field curvature can’t be completely eliminated.
Optical designers use computers to analyze the optics with the internal erector system tilted as it is at adjustment extremes. They examine the aberrations present at this position and “tweak” the curves and thicknesses of lenses to correct for these flaws. These corrections are possible only with state-of-the-art computer design tools and the skill of experienced optical designers.

Zoom ratios of 4:1 and larger require larger internal lenses to accommodate the extended axial movement of the lenses in the erector system. Leupold, for example, always makes the internal lenses large enough to pass all of the valuable paraxial light produced by the objective; they never restrict the objective aperture with internal lenses at higher powers. They do trim the aperture at low power where the exit pupil would get far beyond the capability of the eye’s pupil to encompass, and image quality is better with this restriction.

Barrel and pincushion distortion can affect a shooter’s ability to find a parallax-free position, thinking it some manifestation of parallax. Rolling distortion may contribute in some rare instances as well.

In some forms of competition and hunting, you do not have the time to fine tune parallax or even mess with the knob. With practice, you can develop a cheekrest that will eliminate parallax. In these instances, you might preset the parallax at some mid-range object because the farther you shoot, the greater the error of point of intention, of a steady hold, and of parallax. But at shorter ranges, the error is reduced and the target has an apparent larger hit zone. A little practice with this problem goes a long way.
By Jacob Gottfredson

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Elite Tactical Riflescope

Bushnell’s New DMR 3.5-24x50mm

Bushnell has entered the tactical market, and the result is surprisingly good. From the massive bubble-wrapped genre to the rigors of an upscale tactical riflescope, is this a leap of faith or a change in the manufacturer’s direction?

I reported some months ago on Bushnell’s new Legend Ultra HD binocular. It is a fine piece of glass and goes well with my favorite carry laser rangefinder, which Bushnell also calls the Legend.

They then proceeded to blow the lid off that combo by offering the Bushnell Fusion 1600 ARC! No more having to carry two instruments. And I found the Fusion to work exceedingly well, in many cases to a mile. The bino also tells the rifleman his comeups to the target. I used it during a recent hunt in the Rocky Mountains and was not disappointed.

Now they have entered the tactical market as well. The last few tactical matches over the past year and a half have seen more and more of their new glass atop expensive, competitive tactical rifles.

Having seen them at matches, I was excited to get one in my hands to do a test and review. However, the exercise, over a period of year, was unsuccessful in getting exactly what I wanted. To wit: they have several innovative reticles for holdover as well as wind and moving target holds. What I finally received was a Mil-Dot scope of the Army variety, i.e., big round balls in the front focal plane.

I am a rear focal plane guy, which is strictly a personal preference. There are advantages and disadvantages to each.
In a front focal plane, the reticle has little chance of changing point of impact through power changes, and you can still range and use the hashmarks at any power. But the reticle becomes very small at low powers and sometimes too big at high powers. The rear focal plane reticle does not have the latter problem, but you can become confused and miss a target because the hashmarks change with different power settings.

I remember a befuddling range session with a 7mm Remington Magnum. I would pick a hashmark and miss a shot at a known distance. The rifle had always performed perfectly. I finally decided something was wrong with the scope and started driving home, trying to sort out in my mind what could have gone wrong. Suddenly it dawn on me. I stopped and looked at the power setting. Just as I thought, the power setting was not on max. I returned to the range, put the power on max, and all was once again well. That would not happen with a front focal plane reticle. Still, I can vary the hashmark subtension by simply changing the power on a rear focal plane reticle. If the standard is 2 MOA per hashmark on max power, it is 4 MOA at half power, which presents great flexibility.
By Jacob Gottfredson

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Some Basic Riflescope Theory

Understanding This Tool Is Important.

One source of irritation for this author is the lack of technical data published for consumers about binoculars, riflescopes and spotting scopes. Whereas the camera bugs are given such information, sporting optics manufacturers rarely do it so their consumers can make informed purchasing decisions.

Some of the data essential to scope design simply not published for public consumption include the following:
Modulation Transfer Function (MTF) determines the contrast ratio, or reproduction sharpness of a lens, called spatial frequency and is measured as MTF.

MTF is an important consideration in lens design, defining the ability of the lens to provide contrast and resolution. Camera makers provide MTF curves that allow the consumer to know what the ability of the lens is, where 1 is considered the highest quality. A lens system is considered to be of very high quality when the contrast curve is above .9, and where the resolution curve is above .6. However, many inexpensive lenses will maintain these MTF numbers at aperture settings at or above F-16. That is, if you want excellent resolution, contrast and depth of field from your $400 lenses, have enough light available to operate at high aperture settings.

Many modern riflescopes have stops built into their mechanisms that prevent the aperture from opening all the way for the same reason that superior MTF curves can be kept high by keeping the F-stop high.
By Jacob Gottfredson

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On, Off, On, Off

How Good Are Quick Detachable Mounts?

How many times have you heard the statement, “These mounts return to zero… perfectly”? You’re left with the impression when the detachable mount is taken off and returned, it has no effect on zero or the grouping ability of the rifle and load. Is that true, advertising spiel, or just an aberration?

To test the statement’s validity, I chose three of what I consider the best quick detachable mounts on the market and three excellent shooters. I used a very accurate rifle, capable of .3″, 5-round groups. The groups were shot using a Harris bipod in the front and a competition benchrest bag in the rear.

The handloaded rounds were tuned prior to the test to deliver groups in the .3″ range. The same brass was loaded carefully each time, with five loadings each for the duration of the test. The test rifle was a custom built .308 from Nighthawk with a proven tactical scope.

The tests were conducted at 60′ elevation (approximately sea level), approximately 75 degrees F, 70 percent humidity, and a barometric pressure of 29.90″ of mercury.

The range was 100 yards. To set a benchmark, two of the shooters shot three 4-round groups using normal, tactical rings not removed. The aggregate for shooter one was .338″ and for the second .361″. The overall aggregate was .349″ for six groups of four rounds each. All groups formed in approximately the same location at or slightly below the center dot. It was hoped the zero would not obliterate their aiming point (the center dot) as shots were fired. All but one shot was either in or touching the 1″ inner ring. All were at approximately the same location inside the 1″ ring.
Story By: Jacob Gottfredson

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