Is the BDC portion of the reticle calibrated for 62 grain or 77 grain bullets?

I just got a dimensioned drawing. The numbers line up to a table I just worked up in JBM for 77gr Black Hills (MK262.) My review of the USO SR-8C should be done in a few days.

The R W F reticle for the Uso Sr8C is calibrated for the 77gr SMK going at 2720fps. But you can use other weight bullets.  You just need to plug your numbers for your load on a ballistic calculator. I have all fhe bdc drop numbers in MOA so you can make it work with 62gr bullets

I would stay with Mk262 to insure no indecisiveness in a SHTF situation. When the 4 no longer stands for 400 yards, it allows for potential misses.

I took some pictures of the reticle. They are not the best pics. But it was the best i could do with my Iphone.









Scope at 8x with red dot on



Scope at 1x with  red dot on at brightest setting



Scope at 8x   Dot off

@BigJimFish:
I do follow this thread now since roundabout a year and it is a heart´s desire for me, to thank you for all that time, work and brain you have invested inhere, without having any effort, just to share your knowledge and experience with us.

I can´t tell you how highly I´m recommending your engagement in this, thank you really a lot.
If there would be a medal from arfcom, for respectable members, for their service to the forum, you would have earned it.

But because I´m not able to thank you on this way, I want to give you my respect.
Chapeau!  


But to come back to topic in the end  , I want to ask you only one question:
Which of all those scopes you have had in your hands over the time, would be or is your choice?


Greets from Germany,
Jay  *



(*makeshift for the lack of a beer smiley )

Wow, I have a lot of reading to do.  Thanks for the link to this thread.  Very impressive and exactly the information I was looking for.

I have temporarily removed this review of the USO SR-8C in order to allow the folks at USO more time to send me their comments. It will be re-posted by Friday. It is a courtesy to them and I apologize for the inconvenience.

Thank you for the kind words Jay, I always appreciate the thanks of readers and I am glad you have found my scribblings worthwhile and entertaining.

As for which scope that I have had in my hands would be my choice, that is a difficult question. The easy answer is that right now I am using a Leupold CQBSS, GRSC 1-6x, and a soon to be released 1-6x with a reticle of my design. That doesn't really give you much useful information as, despite liking all three, I didn't pay for any of them, and furthermore, don't get to keep them all.

What you really want to know is what I would buy, or, more to the point, what you would buy if you had the experience of testing all of these yourself. This is a difficult question not just because different people have different impressions after looking though the same optics, but also because different optics excel in different areas such as relative lack of distortion, resolution, size of eye-box, speed, illumination, ranging, etc. Depending on where you live and what your purposes are these factors can vary greatly in importance and therefor change your whole decision matrix. These factors, and my natural verbosity makes for long reviews.

Now that I have said all that I'll give you what you want, or as close to it as I'm willing to go and put out a list of my favorites with a little blurb about why they made the list. I'm not sure what it will be worth. I have left off a great number of very compelling products and some of these I would never buy because they do not best meet my needs or really do all of what I would expect at a given price. Anyhow, here goes. In order of ascending price

Firefield 1-6x24: Nothing this cheap should look this good.
Upcoming 1-6x with the reticle I designed: The best reticle design yet in an excellent optical platform at a mid range price.
GRSC 1-6x: A good reticle design with a solid optical platform manufactured by a leading OEM
Elcan Specter DR 1/4x: Speed kills baby and nothing is faster than this
Swarovski Z6i: Great illumination, great optical platform
March 1-8x ffp: Side focus parallax is a great addition to a solid 1-8x optical platform with excellent adjustments
Leupold CQBSS: It's just so pretty, really, looking through this thing is amazing.

Well, I had all but pulled the trigger on the USO 1X8 but now have to rethink....

Jim, how bright is the Leupold 1X8 by comparison?

It is not a question of brightness, The CQBSS that I had, with the Horus reticle, and the USO are both as bright as you could want a scope to be. The USO illumination has an edge because it is visible to the user thorough the entirety of the eye box range, the Leupold only appears illuminated when you are in the center 3/4ths or so of the eyebox. This can cause the appearance of flickering if your bobbing around a bit.

Thanks, Jim.  I understand now.

Hi Jim, does this occur at all magnifications?  I like a fast acquisition scope with a generous eyebox.  Looks like I am leaning towards the Elcan. BTW, any in depth field test of  the Swaro Z6i or a B&S 1-6x scopes?  Thank for providing a wealth of info on this board!

Review of the U.S. Optics SR-8C 1-8x27mm Scope with C2 Reticle

Les (Jim) Fischer
BigJimFish

Nov 10, 2013


U.S. Optics SR-8C 1-8x27mm scope in an American Rifle Company M10 QD-L mount on a SCAR 16s

Table of Contents:
- Background
- Unboxing and Physical Description
- Reticle
- Comparative Optical Evaluation
- Illumination Evaluation
- Speed Testing and Discussion of Contributing Factors
- Mechanical Testing and Turret Discussion
- Summary and Conclusion

Background:

I first spoke with U.S. Optics five years ago when I was just starting to write reviews. I had not been writing on optics long before I became dissatisfied with existing reticle options, particularly in the variable power low magnification class of scopes, and I contacted them regarding custom reticle design. This was the start of something, in reticle design, that would become a rabbit hole for me. It was also the start of a productive relationship with the staff at USO. They have selflessly given of their time and expertise helping me to come to a better understanding of the workings of optical systems. Expertise they may have in abundance, but their time is a scarce commodity and I appreciate the help, especially that which was given when I was just some yahoo and not a credentialed member of the press.

USO was started in a garage in 1990 by John Williams, an entrepreneurial engineer, and his son. They acquired some equipment and staff gained from Rockwell Scientific following an abrupt reduction in military demand for the products of that company at the end of the cold war era. They were willing to take this significant risk of time and capital because they saw a lack of products in the rifle scope market that were both rugged and designed with the feature sets that a serious precision rifle shooter needs.

The unique approach to the problem of feature sets that USO took was to allow the customer to mix and match whatever he or she wants. Though USO recently began to offer a few stock models (simply the most popular combinations of feature sets), they are alone in that the customer may still build a truly custom scope though them by selecting knobs, reticle, tube size, illumination, and even engraving. This focus on customizability has led USO to have one of the largest stables of reticle designs in the industry as well as a variety of different adjustment knobs and illumination colors. These options are not repetitive or meaningless:  they are designed by shooters and many have been trend starters. The best example of this is probably the EREK knob that started the trend towards zero stops in elevation knobs. They have also been instrumental in the trends towards using the same units for the adjustments and reticle and have also made significant contributions to various aspects of reticle design.

Leaving an introduction of USO without talking about customer service would be remiss of me. USO is a small operation. It comprises less than thirty individuals and is housed in one building. Because of this scale they have control of, and accountability for, product quality as well as selection and education of personnel that is unusual.  As a small business owner I can appreciate the benefits of a smaller, easier to manage, organization. It is this kind of accountability that makes it unlikely that you will need to send a scope back. Nevertheless, scopes contain wear components and, if you use them regularly, eventually you will need these wear components, such as o-rings, serviced. Not only is USO generous when it comes to this sort of thing, but they are also informative and easy to work with. When you call them up it won't be like the USPS, where you find out your package is somewhere in the ether and they are not sure where or when you will get it back. Instead, you will actually find out what is going on. I have even heard of loaner scopes being sent to folks who had a match during the time their scope was being serviced. What I am saying is that, with USO, you can expect to be treated fairly, kept informed, and ultimately satisfied, even in the unlikely event that your scope should have an issue.


Unboxing and Physical Description:

USO's packaging has achieved something resembling cult status. It is so simple and perfunctory that it borders on the absurd. USO scopes come in a plain white box with a label affixed to one end bearing the scope's details and wrapped once around the middle with a piece of packaging tape bearing U.S. Optics name. Despite their simplicity, these boxes are somewhat coveted and easily add $100 to the used sale prices of USO scopes.



U.S. Optics SR-8C unboxing

Inside of the unique box, I found the SR-8C wrapped in bubble wrap and a thick plastic bag. I also found USO logo flip caps as well as a manila envelope labeled with the scope's details and containing the manual paperwork. This scope example probably contained one of the last old style manuals to be produced. I have noted that the USO website contains PDFs of new product line specific (and much more comprehensive) manuals. That is a great improvement as the old manuals were not a cohesive whole, but rather, a few sets of loose instructions. The new instructions booklets are far more complete, contain more and better images, and are organized into a format that is easier for the user to understand.

The SR-8C itself is unusual in appearance. It is, relatively speaking, long, at 12in; thin, at 30mm; and, not surprisingly, on the heavy side, at 34oz. The unusualness in appearance stems from having a much longer section of tube behind the adjustments than in front of them. This is a design feature that I also remember being present in the first incarnation of the Premier Reticles 1-8x that was never to be. I expect this aspect ratio stems from the fact that it is this section of the tube that holds the erector mechanism. This mechanism, which holds the reticle and also the set of lenses whose movement is controlled by the power ring, is responsible for changes in magnification. It makes sense that a massive 1-8x power range might dictate a longer erector tube to allow for more movement. In any case, the result is a unique appearance that is readily identifiable. I do not find the effect unpleasant. The flared objective, holding a larger than most 27mm lens, probably helps with this. Instead, I find the appearance kind of intriguing.

Many of the other features of the SR-8C will be familiar to the user. The SR-8C features the digital illumination control module debuted a few years ago by USO. This unit is much more rugged and water resistant than the previous analog unit. It also close to doubles battery life. As shown in the close-up photo of the turret area later in this review, the brains of this unit are user removable along with the battery by unscrewing its housing. This allows for easy repair, if necessary, and the unit is small enough that a soldier who doesn't trust electronics could conceivably bring a spare. The eyepiece on the SR-8C is the now familiar USO low profile eyepiece with a euro style diopter and a large, knurled, 270 degree throw power ring.


Reticle:


U.S. Optics SR-8C with C2 reticle at 8x focused on a tree line at 100 yards. Haze in the bottom left quadrant is caused by the photography set up and not the optic.

At the time of this writing, four reticles are made for the SR-8C. The most common one, and the one offered off the shelf through distributors, is the 8C mil. This reticle is identical to the no longer offered C2 reticle that my example has, except that the circle feature is absent in the 8C, the cross hair is much finer and both the x and y axis of the cross hair extend to the stadia of the reticle. In practice, four things stood out to me about the reticle. The first thing I noticed is that the circle feature is totally unnecessary for close quarters use. The illumination on this scope is the dominant close quarters feature. The circle is superfluous and I am happy to see it go with the 8C update. The second thing I noticed is that, at high power, the center lines are thicker than I would like. This has also been remedied with the 8C. Overly thick reticles are a curse of FFP scopes and is especially pronounced in this 8x magnification ratio model. Because the reticle is magnified along with the target, it is difficult to find a line thickness that is thick enough to be seen at low power but doesn’t look like a 2×4 at high power. The solution to this is to have more than one line thickness. The center should be stepped down, but that was not done in this case and, therefore, it is difficult to aim precisely at high power for purposes such as establishing a 100yd zero. The third thing that I noticed was that the reticle’s graduations, which have no labels and utilize tick marks of differing lengths for odd and even mils, is not intuitive. For a second I thought the increments were twice as wide as they should be because I naturally assumed the longer lines represented 1 mil divisions with the shorter lines interspersing them at .5 mil increments. This is not the case on this reticle. It is one of the few reticles so graduated that I am aware of. Lastly, a classic mil hash reticle, such as this one, works best when paired with a target style adjustment knob. The zeroing knobs that the example I have is paired with do not match up well with the mil hash reticle for long range shooting. In the future I understand that USO is going to offer a mini EREK knob in this model. That will match up very nicely with their classic mil hash reticle choices.  

The first of the custom shop reticles, and my favorite for this optic by a large margin, is the RWF 3GUN. This reticle, like many in the USO catalog, was designed by a third party who believed enough in his design to put up the cash for ten optics. The reticle mates better than any of the others with the low profile knobs on the SR-8C because it features a caliber-specific BDC section surrounding the six o'clock crosshair. This section is calibrated for MK262 ammo and has drops and windage out to 800yds from a 100yd zero. All four quadrants of the crosshairs are labeled in mils with graduations every half mil. Strangely, the even number mil hash marks are shorter than the odd number hash marks with the 1/2 mil hash marks being shorter still. I found this needlessly confusing and the only outright bad choice in this reticle design. The even and odd hashes should be the same length. The RWF 3GUN reticle has one more innovative feature on it that I proposed some five years ago to several optics makers but no one picked up. It must not have been that bad an idea because it appears that Ron has independently come up with it and used it in his design. That feature is to offset the central close quarters aiming feature, in this case the dot, below the 100yd zero line so that it better lines up with actual close quarters targets.


RWF 3GUN reticle for the USO SR-8C

The SR-8C is also offered with a Horus reticle. Oddly, this reticle is graduated in MOA. I don't like MOAs because the math is a mess. Most people think of an MOA as an inch at 100 yards, but it is not. That angular measurement is referred to as IPHY and has nice easy calculations with multipliers of 100 associated with it. The MOA does not have easy calculations because it is 1.047" at 100 yards rather than 1.000". In the most common equation used, this causes you to multiply by 95.5 instead of 100. Other than the fact it is dimensioned with a unit I have no use for, the Horus reticle looks about like other Horus reticles except that:  the upper quadrant also houses a 90 degree MOA scale, there appears to be a set of caliber-specific windage lines, there are caliber-specific indicator marks for drop, and, lastly, there are two circle features. The design is an unmitigated and virtually indecipherable mess. You start out with a scale unit, in MOA, that no one in their right mind would use because the math is a mess. You go on to stick a secondary scale right in the middle of the upper half, where most folks like to have a little bit of clear space to get an unimpeded look at the target. Next, throw in some circles because circles are fast and two is better than one. Do this despite the fact that the optic has projected dot illumination and doesn't need even one circle to add any speed. Lastly, superimpose caliber-specific bullet drop elements right on top of your already cramped MOA scale. Don't scallop anything, break any elements, or do anything to make things any clearer or mitigate the look of one type of design being dropped right on another. This is the least artful, most cobbled together, abomination of a reticle design that I have ever witnessed. I also expect that it is expensive but I'm not going to bother asking and neither should you. You should choose a different reticle and Horus should spend more time working on designs and less suing everyone for stealing their clearly brilliant ideas.


Horus H-130 reticle for the USO SR-8C. It's like Turducken, except not good.

The last reticle offered is the JNG Mil. I'm not going to go into this one in any depth because it is functionally so similar to the standard 8C reticle that I would not see any reason to pay extra for the custom shop and wait 16 weeks over going with the standard 8C. Bottom line, It is a mil-hash reticle that is a little thicker than the 8C and has a broken circle feature.


Comparative Optical Evaluation:

Over the years I have used a wide variety of USO scopes including the SN-4S 1-4x22, LR-17, ER-25, and ST-10. All of the examples I have used had good to excellent clarity. This SR-8C is no exception. In my testing, it well exceeded the Bushnell SMRS but fell short of the March and Leupold offerings. In contrast to most of the other scopes tested, the color rendition on this USO was on the cool side of the spectrum. It seemed to prefer browns to greens and yellows.

Though the USO has good clarity, it is a quirky optical platform with a number of notable aberrations that I did not notice at SHOT Show, but that became apparent when I had a good long time to sit with it at the bench. These aberrations include curvature of field, pincushion distortion, and eyebox, but the effect they have at low and high power differs, so I will discuss each situation separately.

The most notable distortion at high power is the curvature of field. This shows up around 6x and becomes more noticeable the higher the magnification. Curvature of field is something of a misnamed aberration as it does not make things appear bent, but rather, out of focus. This effect stems from the fact that lenses are usually round, not parabolic, and therefore they do not actually focus all light at a single point. This results in a situation wherein your eye cannot be located at any single place and have the whole image in focus. With the SR-8C, as you move your eye around in what feels like the smallest eyebox in the test line up, you notice different parts of the image coming into sharpest focus. All parts of the field of view can be brought into focus but this cannot be accomplished simultaneously. Each part of the field will only be in focus when your head is in a particular position and that position is different for different parts of the field. Though some pincushion distortion can also be noted at 8x if you specifically look for it, it is really only the curvature of field that is problematic. This aberration is also somewhat unexpected as the USO has the smallest field of view of the 1-8x scopes and it should therefore be easier to avoid this problem in the design.


The exaggerated effect of pincushion distortion on a grid

At 1x the curvature of field is much less apparent. Sitting at the bench, the image appears edge to edge clear. Similarly, you also only notice a slightly greater pincushion distortion in the SR-8C than in the other 1-8x scopes at the bench. When in dynamic use though, users had the feeling they were looking through a straw, or as one described it, an old time telescope. I think that this impression was caused by some combination of a slight curvature of field coupled with a small field of view, tight eyebox, and magnitude of pincushion distortion greater than the other comparison 1-8x scopes. The final effect was that the user felt like the image was kind of cramped and distorted.

Overall, the optical design of the SR-8C does not appear polished, but rather quirky and a little off. The compromises made to achieve the massive 1-8x ratio are apparent to the user and they distract from the scope's functionality.


U.S. Optics SR-8C with C2 reticle and comparison optics at maximum magnification focused on a tree at 100 yards. Haze in the bottom left quadrant on several optics is caused by the photography set up and not the optics.

Illumination Evaluation:

Three years ago when I first started to arrange for this big 1-8x shootout, three scopes were originally slated. These were the S&B, Premier Reticles, and Leupold. The first two of these featured beam splitter illumination technology yielding what is essentially red dot illumination. Not only would getting together this review take an extra two years to accomplish but, in the end, despite containing four 1-8x scopes, it would feature only one of the original three scopes, the Leupold, and would also only have only one scope featuring beam splitter illumination. The USO SR-8C is the optic featuring that illumination technology.

Beam splitter illumination is the most expensive and difficult to manufacture technology in a magnified optic. This technology is commonly used in the simple red dot sights that exist, but it can be adapted to magnified optics with some difficulty. With this illumination technology, the illuminated figure, in all extant designs a dot, is merely projected between the user and the reticle by means of a mirror and is not any part of the reticle itself. In fact, the projected figure is projected at infinity and does not focus with the rest of the optical design. Lining up the projected element with the rest of the reticle is a challenge for this technology and makes the cost quite high. Despite this and other difficult and costly trade offs, beam splitter technology offers some compensatory enticements. These are that, because it works independently from the etched reticle, it can be used in a FFP optic, it is daytime bright, it is battery efficient, it has no down range signature, and it can be easily paired with reflected illumination technology in a scope to allow for dual mode illumination.

This scope does not currently feature dual mode technology, but USO has bandied about doing so in the future. I expect that the manufacturing hurdle to overcome in adding dual mode illumination is that it will probably require a new illumination control module. It was not long ago that USO updated their illumination systems with a new digital illumination module. This scope has that unit. It is easy to disassemble, more durable, offers high pressure water resistance, has field replaceable electronics, doubles battery life, shuts off after an hour when left on, and returns to the previous setting when turned off. In short, it is better than the previous unit in all ways.

It is a shame that, after all these years, only of the 1-8x scopes reviewed included beam splitter dot illumination. This is clearly the most desired illumination technology and, paired with a dual mode system, would give up absolutely nothing to any other tech. It is not a pity for USO though. Their SR-8C has this type of illumination and so beats all others hands down in that arena. I hope that things will come together for the dual mode illumination in the future as well because that would aid in low light long range shooting. I say this while also freely admitting that with any of these 1-8x scopes, given their small objectives, low light long range shooting is probably optimistic thinking regardless of the illumination system.



U.S. Optics SR-8C with C2 reticle and comparison optics at 1x and maximum illumination. Target at 25 yards.

Speed Testing and Discussion of Contributing Factors:


All of the scopes to be compared in the speed testing

Over the course of the last couple of reviews, I have had the opportunity to evaluate, in cooperation with eight or nine different testers, some fourteen different optics, with a 1x setting, engaging close quarters targets. For this I use an air-soft AR and pie pans:  I'm not made of money. It's a lot of fun and you can go though thousands of rounds for the cost of fast food dinner. What I have found after doing all of this testing is that what counts for close quarters is not exactly what you would expect. Here is my summary of the major factors and what part they play:

1) Optical Design:  Having a distortion-free, flat field of view at 1x is, by far, the most important factor to speed. Pincushion distortion, barrel distortion, or curvature of field throws off your ability to merge the data coming in from your left and right eyes into a single image. The result is slow and a little disorienting. This disorienting effect is not noticeable when you are focused on a stationary target, but as you move across the field of fire, having the objects viewed through the optic bend as the field of view moves across them is very hard to deal with. The SR-8C did not score well when it came to the effect of optical design on close quarters speed. The combination of curvature of field with pincushion distortion and a small field of view left the testers feeling like they were looking down a straw. It was the lowest ranking scope tested in this regard.

2) Reticle:  The reticle is a little more subjective. Not every tester has always agreed. However, in general, an open field of view with a few thick objects in just the center is the desired combination. Crosshairs are generally disliked. The C2 reticle that I used, while appearing thick at 8x, becomes quite thin at 1x and therefore does not interfere with the function of the illumination. When you have illumination like the SR-8C, all you need from the reticle for good close quarters performance is for it to stay out of the way. This reticle accomplishes that.

3) Illumination:  Having a daytime bright dot for an illumination system can eclipse reticle design in importance for close quarters performance, provided the reticle can just stay out of the way. That was certainly the case for the SR-8C. There is no competing with beam splitter tech and daytime bright red dots.

4) Eyebox:  It should come as no surprise that having more freedom of motion while still getting a picture is good for speed. However, what I have found is that, within reason, this factor plays less a part than you might think. It is true a tiny eyebox can make an optic slow, but most scopes have enough leeway that it is not a big factor. The eyebox of the SR-8C felt the tightest in the test group and that fact was noted by almost all testers. Low margin for head movement certainly had a detrimental effect on the scope's overall speed.

The USO SR-8C was the most operatic of all scopes in the lineup when it came to speed testing. It was the only optic to be rated fastest by one reviewer and slowest by another. This difference of opinion came down to having the best illumination, smallest eyebox, and most distorted optics. Depending the magnitude of the effect of each of these factors on a given individual, this scope could land anywhere on the comparative speed scale. On average though, it landed in the bottom half.


Mechanical Testing and Turret Discussion:

At the time of this writing, the SR-8C is only offered with capped zeroing turrets. As the name suggests, these are really only intended for zeroing the optic. Though it is certainly no EREK knob, this is probably not a totally fair assessment of these adjustments. Just a few years ago a turret with nice tactile clicks, clear labeling, a zero that could be repositioned, and more than 9 mils of travel was all you could ask for. Today we can ask for much more and, especially given the mil hash reticles that this optic is supplied with, the forthcoming mini EREK will be a significant edition. That aside, these will do fine in a pinch. They are very small but by using .2 mil increments instead of .1 mil, they maintain the best in class feel U.S. Optics is known for and still manage more than 9 mils a turn. The zero reset is accomplished by loosening the two #8 torque screws on the cap and then lifting up and rotating the knob. This is not the slickest system. The adjustments get the job done, though I expected more given the reticles offered and the long range capabilities of an 8x maximum magnification.



Close up of the U.S. Optics SR-8C saddle section. The elevation turret had been disassembled as well as the illumination module.

For the adjustment testing of the USO SR-8C and other scopes being reviewed this year, I made up the new target shown below. I spend a good deal of time shooting at my local 100-yard range with scopes that are adjusted in mils. It annoyed me that I could not find a target made on a mils at 100 yards grid. I therefore made one and furthermore, made it have six bulls so that I can shoot a box and power change test on the same target. The grid on the pictured target is .1 mil at 100 yards. I will make the PDF of this target available just as soon as I can figure out a way to get the CAD program to make a PDF of the correct size. (It seems to be able to print out the correct size, but the PDF is not right. I will have to use some printer plug in.)

A box test checks for the accuracy in magnitude and independence in direction of the adjustments. To perform this test, the shooter aims at the same place when firing all shots, but moves the adjustments between groups such that a box is formed by the groups fired with the last group landing back atop the first. This box should be square and the corners (i.e. the groups) should be the correct distance from each other as dictated by the scale of the scope's adjustments. As performed on this target, all of the groups should have the same position relative to the exes. The USO passed this test with no difficulty.

In a power change test, the rifle is fired at two different targets with one being shot at maximum magnification and the other at minimum. The targets are then compared to make sure that the scope does not shift with regard to point of aim when the power is changed. Some shift is expected with a second focal plane scope, but a front focal plane scope, such as this one, should exhibit no shift. The USO exhibits no shift.


U.S. Optics SR-8C box and power change test targets

Summary and Conclusion:

When I left SHOT Show last year, this USO was one of my favorite products. I was anxious to get some real time with it and see how it stacked up. Obviously, I am a bit disappointed. With some quality time behind the optic, and with other optics side by side, significant aberrations became apparent both by comparison and even when viewed alone. 1-8x scopes have incredibly high erector ratios and accomplishing that without noticeable sacrifices is not an easy task. It is also not an easy task to provide daytime bright illumination. This is a task most competing scopes fail at but at which the SR-8C is successfully.

Beyond the foibles with the optical platform, which are the crux of my complaint, I found some important features meshed poorly. Mil hash reticles, loved by many (though honestly, not so much by me), pair best with feature rich turrets. The 'dial for drop, hold for wind' usage mode is a fast and effective distance compensation method, provided the distance to the target is already known, and works best when a high clicks per revolution with zero stop elevation turret is paired with a mil hash reticle. The current incarnation of this design does not have the turrets to best accomplish this. Similarly, round specific bullet drop reticles pair well with diminutive knobs. This scope has the knobs but the reticle for this, the RWF 3GUN, is custom shop only. That reticle should be the standard with these diminutive adjustments.

I should also mention the fact that, currently, no MOA adjustment graduations are available to pair with the Horus H-130 MOA reticle. If I could think of a reason for any anyone to purchase this reticle, that would be a problem.

I expect that some of my issues will be remedied in the future and also that some new features slated will make this a much more desirable optic. The forthcoming mini EREK will pair quite well with several of the existing reticles and a new dual mode illumination control module would complete the illumination domination of the SR-8C.



Here is Your Pro and Con Breakdown:

Pros:
Best in class illumination and the possibility of dual mode illumination in the future
Clarity is good
Adjustments pass the box and power change tests
Mini EREK knob expected in the future that will offer high mils per turn and zero stop
U.S. Optics' excellent warranty and best in industry customer support


Cons:
Significant curvature of field apparent at high magnifications
Small field of view
Curvature of field, pincushion distortion, small field of view, and small eye box all combine at 1x to give the appearance of looking though a straw
Limited adjustments make the standard reticle less desirable
Heavy



U.S. Optics SR-8C 1-8x27mm scope in an American Rifle Company M10 QD-L mount on a SCAR 16s

To the first question on Leupold illumination, yes.

With regards to the second question, I'm not sure what a B&S 1-6x is but I will address depth of field a bit. Scopes do have varying depth of field with fixed parallax and adjustable objectives being generally more forgiving than side focus parallax. Only occasionally have I seen discussion on this point and I have never seen anyone try to actually measure it. I believe that the reason for this is probably that as you look through your scope at objects at different distances your eye is constantly refocusing. It's not like taking a photo where the whole of the photo will be taken at one time, in one focus. Your eyes focuses on very small portions of the scopes field of view at a given moment time and whenever you switch what you are looking at you will refocus as well. This makes depth of field both less important in a rifle scope and far more difficult to measure. In short, I don't have a depth of field test between those two optics or any other two.

I find the idea of comparing depth of field interesting in rifle scopes intriguing. There are a variety of optical concepts that I have considered tackling in more depth. I have thought about doing parallax tests at different distances as well as more well defined resolution tests. So far I have avoided increasing the technicality of my testing though. The primary reason for this is that the first one of these tests, exit pupil, that I did had results that did not prove helpful the reader as they were not as meaningful to user experience as I had hoped. Instead, the results became more of a stumbling block than an aid to good scope selection. People tend to value numbers higher than words and that test produced numbers that were less meaningful but perhaps more compelling than the subjective evaluation of the product. Since then I have continued to do more technical tests but I have not included these in my writing because I have not yet found any results that I have thought particularly meaningful as compared to less technical, more subjective commentary. I don't really anticipate this state of affairs changing in the future.

Picked up a Vortex PST 1-4x recently, need to sight it in.

Its really nice but for the distortion around the edges at the lowest power.

I was also considering the Leatherwood CMR4 as well... from the pics I have seen online, it looks like there isn't much if any distortion. Is the CMR4 better in the optics area than the Vortex? I haven't found much info on it.

The Vortex warranty makes a huge difference though even if it isn't as good optically, but sufficiently good glass could sway me to switch.

Hi Jim, apologies but B&S meant to be Schmidt and Bender.

And I did not mean depth of field but an in-depth review and field test of the Swaro Z6i and Schmidt and Bender 1-6X variable scopes.

Thanks!

I read (a lot of) this thread, several other reviews online, and talked to a friend with an Burris MTAC and a Vortex PST. So I've done a lot of my homework, but I wanted some feedback here before pulling the trigger on anything.

The rifle this will be going on is a 16" flat top carbine with a FF rail (actually, the ARFCOM Cyber Monday rifle). Intended uses: plinking, home defense (currently using a Glock -- my other AR has irons), and 3 gun (in the future -- not competing now). Ranges: 10 - 300m.

After reading several reviews, here are the important features to me:
- Suitable for both eyes open (like a red dot) daylight shooting at 1x, this means good illumination and a good sized reticle
- Large exit pupil to give some leeway in cheek weld
- Low price (~$400 or less)
- Bullet drop reticle (I'm OK with 2fp and BDC only on max mag)
- Durable

Scopes I'm looking at (in order of consideration):

Burris MTAC: nice fat BDC reticle, ~$320 on Amazon, supposedly good illumination. I see exit pupil listed at 24mm/6mm 1x/4x, and I gather those are "theoretical" numbers so someone please let me know if it has such a generous eyebox. Some negative comments about distortion at 1x.

Primary Arms 1-6x: I can't find anything about this scope! PA is having a blemish sale on them for $200 currently. link The diagram of the reticle looks nice, but I haven't seen an actual photo. I like the higher magnification on this one, but I'm hesitant to buy one until I can find a review online or at least some actual reticle photos. Also, the exit pupil numbers don't look too good but I'm no expert.

Bushnell AR Optic 1-4x24: positive review here, though many in the thread don't seem to agree. Several users in the thread claim that the weak illumination and ffp architecture make it unusable as a "red dot" type sight on 1x.

I would have included the GRSC if it was still in production. The new one is out of my budget, I think. I also considered the Vortex PST but I prefer the MTAC's reticle (based on photos).

BigJimFish, could you post results of your target acquisition speed test? I am one of those people who focuses on numbers like exit pupil , so maybe the results (times?) would be more informative regarding both eyes open, red dot type shooting.

So far I am not a happy camper.  Nothing is coming together for me.

USO has great day illumination with a dot on the SFP, but is heavy and makes you feel like you are looking through a straw (although FOV is 83 vs 92 for the MK8 at 1x which isn't much wider).

Leu MK6 illumination and dot size and dot wavering as head moves at 1X leave folks wanting.

Vortex is SFP.

Leu MK8 is super expensive and suffers the same issues as MK6

Upcoming Trij VCOG - turrets don't match reticle, among other things

Sure wish I could take the USO dot on the SFP and put it together with the MK6 package.

Seems like that would be a winner.

Or even better, if USO could get their FOV increased by 25ft .  Then I would still get 8x without looking through a straw.

I, too, would like to thatnk you for all of the hard work that you put into this in order to help us make the most informed decision when purchasing a scope.  I have been following this thread for awhile but remained confused as to which way to go, as all the scopes seemed to missing one thing or another.  I just about to ask some more questions about the GRSC when I saw your post above.  I think for me and my budget, the GRSC is the way to go.  However, I see that you're going to team up with a scope maker who's going to use a reticle designed by you?  This seems interesting to me.  When will yhou have more details on this?

Sorry, it's probably bad form to speak for Jim, but I'm also excited about the new 1-6x and emailed him about it.

He said he'll announce more details this week.

The review will be posted this week and the product introduced at Shot Show. The review includes all of the usual analysis plus an extended reticle section that explains the design and use of the reticle. I am very proud of the design. It brings together all the things I have learned in the past 4 years of testing, analyzing, and writing about scopes in this class. I am also quite pleased with the optical platform that Optisan has put together for this scope. The clarity is excellent, on par with some significantly more expensive Japanese offerings, and the flatness of field at 1x is the best I have tested. You can read about all that soon though.

Thank you for the response, and I'm looking forward to seeing the final product.

Just noticed this thread after I had already posted a thread w/ a review of the SWFA 1-6x24.

Review of the Optisan CX6 1-6x24mm scope with Mudskipper 3 reticle of my design.

Les (Jim) Fischer
BigJimFish

Jan 11, 2013


Optisan CX6 (prototype markings) with Mudskipper 3 reticle on a SCAR 16s

Table of Contents (my way of apologizing for the fact my reviews are detailed):
- Background
- Physical Description and Illumination
- Reticle
Close Quarters Reticle Features,
Ranging Using the Mil-Dots:
Ranging Using the Width Brackets
Ranging Using the Power Ring Method
Drop and Wind Compensation
- Comparative Optical Evaluation
- Speed Testing and Discussion of Contributing Factors
- Mechanical Testing and Turret Discussion
- Summary and Conclusion

Background:

Optisan is known for precision optics throughout Europe were they are famous for their commitment to product development and innovation.  Though you have likely not heard of them in the US before reading this article, it is very unlikely that you have not seen their products, as they are a large manufacturer with a variety of mainstream clients. Optisan has built a reputation for high quality products, such as the MTC-Viper scope line, and attention to detail in all aspects of European design and have the endorsement shooters like World Hunter Field Target champion Gary Cooper.  Optisan is a global manufacture with ISO9000 certified manufacturing facilities in three countries.  

That brings us to my association with Optisan:  an important point as you will soon see. As I have mentioned before, that last day of SHOT Show, where I walk around the whole exhibition looking for shiny things to catch my eye, has always proved the most profitable. Two years ago I happened upon Optisan's booth, looked through an optic, scribbled a little bit in my notebook, and started to leave when I was stopped by Lily. She wanted to know what I thought and I obliged. Being as I ramble on, this took a few hours and at the end of it, I was designing a reticle for them. Optisan had been looking for a knowledgeable individual to help them align the features of a new scope line to be released in the U.S. with the desires of the U.S. market. My experience in reviewing scopes of the 1-(n)x class for the last four years proved the resume for this job. Two years later, I have created what I believe to be the best reticle design for the 1-(n)x scope class and have a patent pending on it. The scope, in conjunction with the reticle, are designed to truly enable the shooter to utilize the full effective range of the modern sporting rifle platform. 3-Gunners will love it.  I will now review that scope, admittedly not in a completely unbiased way.


Physical Description and Illumination:

What you see before you is a late generation prototype of the CX6 1-6x24mm optic with the Mudskipper 3 reticle. The optical platform and mechanicals on this prototype are complete and final, though the markings and finish differ from the production version. The prototype I have was supplied with the excellent set of metal flip lens caps that will be included with the production version. These are screw on, indexable, and when fully open are almost flat to the tube. They are second only to Leupold's $80 per set Alumina caps and are far beyond anything else.


Optisan CX6 1-6x (prototype markings) uncapped adjustments with the objective lens flip cap in the foreground

At 10.5" long and 17.5oz, the CX6 would be about average in dimension for a 1-4x scope:  putting it on the good side of average for a 1-6x. It features low profile turrets, and a euro style diopter that is smooth but a bit on the light side. The power ring feel is perfectly smooth and exactly the right stiffness with a throw of 180 degrees. The illumination control is in the usual location on the left side of the saddle. It offers six intensity levels of red illumination with off points in between. The knob houses the CR2032 battery and rotates smoothly and with the precise amount of force you would want. The lowest setting is just visible in a dark room and therefore probably a bit much for night vision. The highest setting is visible in daylight, but not bright. It is a reflected illumination system and the brightness is perhaps just above average for that type of system. The entirety of the reticle is lit when illuminated. One of the two caps for the adjustments holds a spare battery. This cap is slightly higher than the other and can be affixed to either the elevation or windage knob.


Optisan CX6 1-6x with mudskipper 3 reticle and comparison optics at 1x and maximum illumination. Target at 25 yards.

The overall build quality of the CX6 looks very good. The machining is clean and everything rotates smoothly. The Optisan name is even intricately engraved into the eyepiece housing by what appears to be a very small end mill. This is a nice touch.


Reticle:


Optisan CX6 with Mudskipper 3 reticle at 6x focused on a tree line at 100 yards

To me, the reticle is the most interesting problem of rifle scope design. It is interesting because, unlike most other design problems, more cost does not equate to a better product. You can enhance the clarity of your scope by buying better glass or, more importantly, better grinding and coating; you can boost your magnification ratio by adding glass with a high index of refractivity; and you could (though I don't know of any scope companies who do) minimize distortions by adding aspherical lens elements as many cameras do. All of these enhancements are primarily cost limited; a reticle is basically not. One engraved reticle is not significantly more expensive to make than another, yet the difference to the scope's utility is usually far greater than the difference between high cost glass and low cost glass. The problem of reticle design is one of limited real estate and divergence of application. Speed often conflicts with flexibility, as well as accuracy, and every element you add to the design may serve to interfere with any other element or may just confuse the user. It is a pure engineering challenge in two dimensions:  a balancing act that you can't buy your way out of. Those who have read my reviews know that few scope makers produce what I would term a success in this endeavor. Because of this, I began toying with designs myself four years ago. The Mudskipper 3 reticle (patent pending) in this Optisan CX6 scope is the first product of those efforts. I believe that it offers the best balance of ranging, distance compensation, and close quarters features for the short to mid range tactical scope of any design extant.

The first thing to understand about the short to mid-range tactical scope is that it is being asked to do a few fundamentally very different things. At close range it is expected to provide a quick, easy to acquire, aiming point that does not have to be very precise. At longer range it is expected to aid the user in both calculating range and compensating for the drop and wind drift of the projectile at that range. These calculations and compensations should preferably be somehow precise, quick, and easy to do. It is therefore not surprising that there is a high degree of difficulty involved in putting together a system that fulfills all of these requirements with a few scratches on piece of glass. The way I tackled this problem was to break it down into modes of use. There are three rangefinding modes, two distance compensating modes, and one close quarters mode. Each of these modes required reticle features which were then sorted out such that, wherever possible, a reticle feature was adapted to be used in more than one mode and, where conflicting, that conflict was mitigated to the greatest extent possible.

Close Quarters Reticle Features:

First I will talk about close quarters use since this is the primary function of 1-6x scopes. Through my extensive testing and reviewing experience, I have found that the key elements to speed with respect to reticle design (in the absence of bright dot illumination) are a relatively clear field of view and few large central elements. In this scope, there are two central elements:  a thick scalloped circle and a thick diamond. In order to gain the function of a clear field of view, all other elements in the reticle are very thin. Furthermore, the top vertex of the diamond forms a nice precise 100-yard zero for those who, like me, demand a precise primary aiming point in an optic. The center of the diamond feature is therefore offset below the 100-yard zero. I have also offset the center of the circular element. This is because the aiming point for close quarters targets should be below the 100-yard aiming point, owing to vertical offset of the scope from the rifle bore. This is only done in one other scope design that I am aware of, but it is a definite improvement on other aiming point designs. The overall effect of these design choices is that this scope is very fast at 1x:  faster even than many bright dot illuminated scopes.

The Mudskipper 3 reticle offers three different modes for determining target range. Two of these you will no doubt be familiar with, though you will never have seen them combined in this way. The third mode will bring back an old and forgotten good idea in a new form. I think that the easiest way to properly convey to the reader each of these modes is to walk the user through using each one in the manner that might be approached in the owner's manual. While the reticle is designed to be easy to use and uncluttered, its combination of a number of systems does render explanation necessary.  I apologize in advance for the length of this section:  I made the decision to sacrifice brevity to understanding.

Ranging Using the Mil-Dots:

The first mode of determining range is the mil-dot mode. To this end, a string of vertical mil-dots and a string of horizontal mil-dots have been incorporated in this reticle design. These dots are calibrated to be the correct distance apart when the scope is set to 6x magnification. At this power, the dots are spaced 1 mil center-to-center, with the outside diameter of the dots being .1mil. One mil is 3.6" at 100 yards or 10cm at 100 meters:  it is an angular measurement and therefore is also 36" at 1000 yards and 1m at 1000 meters.

These dots may be used to estimate the range based on either a vertical or horizontal dimension where the actual size of a target is known. To accomplish this, the target should have its width or height in mils measured with the scope set on 6x. This dimension (in mils) will be input into one of the following ranging equations along with the target's actual size (in inches or yards):


Optisan CX6 with Mudskipper 3 reticle at 6x ranging a IPSC target at 362 yards using the mil-dot method.


Ranging Using the Width Brackets:

The second mode of determining the range of a target is to use the set of brackets calibrated to represent an 18" width at distances from 300 to 800 yards. There exist in the market today many scopes that offer a ranging feature based on the width of an 18" full size IPSC plate target at distance. Most of these scopes also integrate this ranging feature with the distance-compensating drop lines. Though this ranging method is woefully inaccurate; it is the fastest, is familiar to most shooters, and takes no extra space since drop lines of some type must be incorporated for distance compensation purposes anyway. For these reasons, this feature has been added to the Mudskipper 3 reticle. In order to use this feature you should bracket the 18" wide dimension within the drop line of appropriate width at 6x. That line corresponds to the distance of the target. Only two of these lines are directly labeled:  5 for 500 yards and 7 for 700 yards. Lines exist from 300 to 800 yards and the identity of unlabeled lines may be inferred from their neighbors. In the below example, the width bracketing/drop lines are highlighted in green and the full size 18" IPSC target is in blue.


Optisan CX6 with Mudskipper 3 reticle at 6x ranging a IPSC target at 700 yards using the width-bracket  method.


Ranging Using the Power Ring Method:

In addition to the first two relatively common ranging modes already mentioned, this scope also offers a third and much less common method. Although originally developed during the Cold War and used in flagship optics by both sides of the conflict; power ring ranging has only occasionally appeared in products since. This ranging method offers a remarkable combination of accuracy and speed, and it works because in a 2nd focal plane scope, the relationship between the size of the target and the size of the reticle is not fixed but rather changes in a predictable manner with changes in magnification. In this implementation, the inner diameter of the large circle where not scalloped away is calibrated to be 5' 10" at whatever distance is labeled on the power ring. In practical shooting competitions, the target is often placed at about this height for reasons we will not here discuss. This can be true for full size IPSC steel, but is more often true for the more popular smaller targets, such as 10" square plates. To range such targets, the user need only bracket the target within the ring and turn it until the target fits height-wise. The range can then be read off the power ring with excellent precision. In the below example, the full size IPSC target is in blue and the ranging circle is highlighted in green. You will note that the target is suspended on a post so that it is the correct height above the ground. Prepare yourself to be amazed by the speed, ease, and accuracy of rangefinding using the power ring method. This method offers a better compromise of speed and accuracy than either of the aforementioned methods in that it doesn't compromise either.


Optisan CX6 with Mudskipper 3 reticle at 6x ranging a IPSC target at 500 yards using the power ring  method.


Drop and Wind Compensation:

Though knowing the range to a target is nice, it is merely a means to an end. That end is to be able to compensate for the drop of the bullet due to gravity and the drift due to wind. Though the mil-dots in this reticle may be used to accomplish this and represent the first of the two distance compensation modes (the 100-yard point of the diamond is exactly 1 mil above the first dot), this reticle is primarily designed and calibrated for use with the M855 62gr .223 cartridge fired from a 16" barrel AR15. The exact ballistic table used is given below for the edification of the more advanced reader. This reader, who I expect also hand loads his or her own ammunition, will be pleased to know that SierraTM makes an affordable 65gr .224" GameKingTM bullet with a BC of .303 that can be loaded to be virtually indistinguishable from M855. It is also of note that the ballistics of this specific cartridge do not differ extraordinarily from those of the popular 55, 69, or 77 grain .223 loadings, or even from many .308 cartridges. It may be used without too much difficulty on all of these cartridges, though there will be some error due to the differences between the rounds. Shooters planning on using these or different cartridges should consult the table below in comparison with a similar table for their own cartridge. This will allow the user to be cognizant of, and adjust for, the exact magnitude of difference to be expected at each range.


Typical M855 Ballistic data as fired from a 16" barrel AR15

Using the target range calculated by one of the above methods and the wind speed whose calculation I will not go into at this juncture, the user may compensate for the drop and drift using the drop lines and 10 mph windage bars engraved in this reticle. These drop and drift compensating features are supplied for between 300 and 800 yards. In the below example, a target at 700 yards with a 5 mph left to right 90o crosswind is being appropriately targeted using the drop lines and 10 mph windage bars on the reticle. The drop lines have been highlighted green, the ISPC full size target blue, and the 10 mph windage bars pink.


Optisan CX6 with Mudskipper 3 reticle at 6x engaging an IPSC target at 700 yards with a 5mph 90degree left to right cross wind using M855 ammunition fired from a 16" barrel.


Comparative Optical Evaluation:

I had this scope during the time I did the 1-8x reviews and I evaluated its speed and illumination at that time. However, I made the mistake of not also evaluating its clarity, distortion, color rendition, and other aspects of the view at that time. This was a mistake because when I evaluated the 1-8x scopes it was summer and warm and nice. When I did the Optisan CX6 evaluation today, it was 10 degrees with snow on the ground. The advantage of this is that snowy conditions are tough on optics. It is bright, your pupil shrinks, and I think this makes the eyebox seem much smaller. There is also bright light reflecting off the snow from all directions. If the optic is going to have a stray light problem, you can bet it shows up on a snowy day. The only thing that is made more difficult to evaluate is the color rendition since pretty much everything is either white, black, or brown. For comparisons to the Optisan CX6 I brought out the GRSC 1-6x, a Zeiss Conquest 4.5-14x, and, because I still have it for the moment and it is pretty, the Leupold CQBSS. All scopes were set at 6x for all the comparisons except distortion, which is more important at 1x because it can interfere with the proper merging of images from both eyes but is relatively unimportant at 6x.

The first thing that I noticed in my testing was that the difficulty in conditions highlighted the differences in the size of the eyebox at 6x in the scopes. The Optisan and Leupold felt roomy and comfortable; though not to the extent of the 44mm objective traditional long range Zeiss scope. Large objectives can translate into large eyeboxes. The GRSC was cramped under these conditions and difficult to accurately assess with regard to resolution because very little movement was necessary to detrimentally effect its clarity. Similarly roomy was the Optisan field of view, which was far larger than both the GRSC and Leupold although smaller than the Zeiss.

I came to the conclusion, after a good deal of time evaluating, that the Optisan CX6 has slightly better clarity than the GRSC and is significantly better than the Zeiss. Not surprisingly, the Leupold is the best. It was really very hard to make a judgment between the Optisan and the GRSC because they seemed to be very close and the difficulties with regard to eyebox that the GRSC was having in these conditions added a further complication. In the end I gave the edge to the Optisan mostly because in the event two scopes look very close but the image always appears at top clarity though one and only fleetingly though the other, I think you have to go with the better user experience.  

None of the scopes in this testing have major issues with any of the usual optical problems. Chromatic aberration was a little more visible on the Optisan and GRSC than on the other two but not by much, and it was certainly not a big problem, especially given the conditions of testing being absolutely ripe for it. Neither the Optisan nor any of the other scopes displayed much in the way of the (very poorly named) curvature of field. Lastly, the Optisan is outstanding with regard to pincushion or barrel distortion. The field is amazingly flat. This is especially important at 1x where it gave this optic a significant edge in speed testing. I believe the Optisan CX6 has the flattest field of view at 1x of any magnified optic I have tested.

The last two things to talk about are color rendition and glare. Today's conditions were great for testing glare and terrible for comparing color. From what I can tell, the CX6 color rendition is relatively neutral. It is certainly not as green loving as the CQBSS, which can find the moss on tree bark even in the winter. Whether it lies right in the middle or a little bit towards the preferences for greens, I'm not sure. As for the ability of the  CX6 to handle off-axis light:  it is exceptional. I was unable to create any artifacts or washout of the reticle at any angle from the sun. Given how the objective is recessed in the design and further recessed by the flip-up lens cap housing, I believe this excellent performance was achieved the old-fashioned way:  by simply shading it.

The question I asked myself going into this project (and that I have been asking myself for some time as the quality of Chinese produced optics continues to improve) is whether the Chinese can produce optics that are competitive with the Japanese but at a more attractive price. Though in the primary comparison in this evaluation we are comparing a second focal plane optic (the $600 Optisan) with a first focal plane optic (the $1,000 Japanese GRSC), not a totally fair comparison, the second focal plane Optisan is unquestionably better optically on balance. It is clear to me that the Chinese are now quite capable of invading the mid-priced market and, given the price difference, I expect they will dominate it in fairly short order.



Optisan CX6 with mudskipper 3 reticle and comparison optics at 6x focused on a tree line at 100 yards


Speed Testing and Discussion of Contributing Factors:


All of the scopes to be compared in the speed testing

Over the course of the last couple of reviews, I have had the opportunity to evaluate, in cooperation with eight or nine different testers, some fourteen different optics featuring a 1x setting by engaging close quarters targets. For this testing I use an air-soft AR-15 and pie pans:  I'm not made of money. It's a lot of fun and you can go though thousands of rounds for the cost of a fast food dinner.

What I have found after doing all of this testing is that what counts in an optic for close quarters speed is not exactly what you would expect. A distortion-free image is the dominant factor. Specifically, the field of view must be flat and magnification very close to a true 1x must be maintained. This is because the merging of images from the right and left eyes is paramount. Distortion, such as pincushion or barrel, or an image that is too large or too small will make that process difficult and disorienting.  Following distortion in importance is the combination of reticle and illumination system. I say combination because what is needed, which is a relatively open field of view with one or more difficult-to-miss central features, can be accomplished either with the reticle or with a bright illuminated dot. Lastly, the eyebox of the optic must also be large enough that some movement of the shooter's head is accommodated. While bigger is certainly better in this area; there is, in effect, a law of diminishing returns:  at some point, the eyebox is simply big enough and making it larger has little benefit.

The performance of the Optisan CX6 with Mudskipper 3 reticle in close quarters testing was excellent, especially for a scope that features traditional reflected illumination. The CX6 had the least pincushion or barrel distortion in any scope I have ever tested. This, combined with an accurate 1x setting, allowed for a seamless merging of images between the right and left eyes which was described as very comfortable by testers. Furthermore, the central circular and diamond figures in the Mudskipper 3 proved to be sufficiently thick to hold the shooter's focus while all the other features proved sufficiently thin to be ignored. This allowed for the quick and easy establishment of aiming point despite the lack of a daytime bright dot type illumination system. Lastly, the eyebox of the CX6 was on the larger side of the optics tested and proved sufficient.

The cumulative effect of all these factors was that the CX6 with Mudskipper 3 reticle finished reliably well above average in the speed testing. There was little disagreement among the testers on this point:  with the scope even finishing first in the opinion of a tester who was not me. Most testers were not aware during the testing and review process that they were talking to one of the scope's designers.


Mechanical Testing and Turret Discussion:

The Optisan CX6 features exceptionally low profile capped turrets that protrude less than 1/4" from the saddle. The turrets have .5" per 100 yard clicks and have a sliding zero indicator/scale that is held in place by friction and only visible from above. 44" per revolution of travel is present and the indicator is labeled with this as well as the direction of aim point movement. The clicks are easily audible and also tactile; though they are very mushy and the extremely low profile format requires ungloved hands to manipulate them. In short, these are unadulterated zeroing turrets. They are designed to be used only during the zeroing process and are therefore as small, light, and unobtrusive as possible. All distance compensation is designed to be done via the reticle. The turrets serve their purpose well but would be totally unsuitable for anyone desiring to compensate for distance using only these adjustments.

For the adjustment testing of the Optisan CX6 and other scopes being reviewed this year, I made up the new target shown below. I spend a good deal of time shooting at my local 100-yard range with scopes that are adjusted in mils. It annoyed me that I could not find a target made on a mils at 100 yards grid. I therefore made one and, furthermore, made it have six bulls so that I can shoot a box and power change test on the same target. The grid on the pictured target is .1 mil at 100 yards. I will make the PDF of this target available just as soon as I can figure out a way to get the CAD program to make a PDF of the correct size. (It seems to be able to print out the correct size, but the PDF is not right. I will have to use some printer plug in.)

A box test checks for the accuracy in magnitude and independence in direction of the adjustments. To perform this test, the shooter aims at the same place when firing all shots, but moves the adjustments between groups such that a box is formed by the groups fired with the last group landing back atop the first. This box should be square and the corners (i.e. the groups) should be the correct distance from each other as dictated by the scale of the scope's adjustments. In this instance, I obviously used a mil target with inches per 100 yard adjustments and therefore the relative positions of the groups to the x's will not be expected to line up and a measurement will be necessary. The box formed by the CX6 is nice and square with the last group landing well atop the first, indicating adjustments are independent and  return to zero. However, the distance of one group to the next was about 4.125" instead of the 3.75" dictated by .5" at 100 yard clicks. This means that the clicks are more like .55" than .5." I have been told that this issue with the magnitude of the click adjustment is present only on the prototype and has been fixed in the production version. Either way, people using the adjustments only for zeroing, as they are intended on this optic, will not be inconvenienced by this.

In a power change test, the rifle is fired at two different targets with one being shot at maximum magnification and the other at minimum. The targets are then compared to measure the shift with regard to point of aim when the power is changed. Shift is expected with a second focal plane scope but a front focal plane scope should exhibit no shift. The CX6 exhibited a shift of roughly 4 MOA down when going from 6x to 1x. Since this is a second focal plane scope and shift is intrinsic in all second focal plane scopes when the adjustments are in any position except absolutely centered, this test has no real meaning except to remind the user that with any second focal plane rifle scopes, all precision work should be done at the same power and that should be the power the scope is zeroed on. The reticle of this scope is calibrated for this to be the maximum magnification of 6x.


Optisan CX6 1-6x box and power change test target


Summary and Conclusion:

I was apprehensive about this project at the start. Prior to SHOT Show, I had never heard of Optisan and the 1-6x prototype that first year was not confidence inspiring. I agreed to design a reticle for them because I figured it might be an interesting experience and I had only my time to lose. It turned out to be a whole lot more time than I anticipated but also a much better product.

The optics in the CX6 turned out much better than I expected. In virtually all aspects of optical evaluation, it betters products from the leading Japanese manufacturer selling at the $1,000 price point and its flatness of field at 1x leads all scopes I have tested, contributing greatly to its outstanding speed. I am also more pleased than I expected to be with the final reticle design. I did not have the luxury of having multiple prototypes made with which to hone fine design elements, such as the line widths, or with which to test novel features, such as the overlapping of the drop lines and mil dots or the power ring ranging feature. In the end, the power ring ranging proved to be faster and more accurate than I imagined it could be and the only change I would have made to the rest of the design would be to decrease the line width on the drop-indicating numbers. Given how many designs littered the cutting room floor, such satisfaction with the first physical product was not anticipated.

The only downsides to this scope are the slightly errant adjustment increments, the brightness limitations inherent with all reflected illumination systems, and the relative newness of the Optisan label in the American market. These first two factors are heavily mitigated by the reticle design and the third, well, nobody gets to start out as a household name with a huge distributor network. With scopes like this, I expect that will come soon enough.  

Here is Your Pro and Con Breakdown:

Pros:
Mudskipper 3 reticle, the best close to mid range reticle ever designed
One of the fastest scopes tested
Distortion is minimal, has the flattest field of view at 1x I have tested so far
Clarity well above its price point
Build quality looks and feels high
Really excellent metal scope caps are included
At $600 it is affordable


Cons:
Adjustment increment is not accurate on the prototype (I am told they are on the production scopes)
Reflected illumination is never daytime bright
New brand



Optisan CX6 (prototype markings) with Mudskipper 3 reticle on a SCAR 16s

Optisan 1-6x = another low cost, questionable quality, chinese manufactured scope. The reticle design (no offense) is a bit cludgey. Joins a large field of low end, not for hard use scopes.

That's the last post content before Shot Show. Be sure to follow my 2014 Shot Show Blog the next couple of weeks as only pertinent content will show up on this page.

This remains to be seen. The glass is comparable with much of the stuff coming out of Light Optic in Japan and being used in $1,000-$1,500 optics. It remains to be seen, for me anyway, the durability of the mechanicals, but to classify this line of optics as similar to other low end Chinese optics is not accurate and I believe furthermore underestimates the capabilities of many Chinese facilities. My last Nikkor camera lens came out of China. Nikon now does most of their manufacture there (admittedly they also subcontract some shamefully bad products in China.) Japan once made junk and now beats the Germans in many products.

Bottom line, I don't think that made in China an accurate byline for poor quality optics any more and I don't think this is just another scope near the $500 price point and that has nothing to do with my having designed the reticle.

Jim,

Can we see the (numeric) data from your speed testing?

Is your statement based on in field, in competition, in hand or at the range use?

Where and when can we buy the optizan mudskipper3?

(Forgive me if it was mentioned already)

You didn't include the Trijicon TA 31 RCO M150 on you list of scopes to Review.  However S&B, US Optics and Nightforce was there though all good scopes

I am in somewhat of the same quandry myself. I had originally started looking for a 1-4 power a couple of years ago. The big difference is that I do not need it for an FAL, just an AR. At my age, I feel like when the option is there to get a little more power 1-6 vs 1-4 for a little more money I need to opt for the additional power.
Then the next thing I know I am wanting illumination.

I guess if I want and save long enough, what I want will come along. I am now interested in the Burris XTR-II but I believe it starts at 1.5 power. We shall see. Good luck in your quest.

If you can live with 4x, SWFA has a great package deal on the old 1-4x XTR which is a true 1x. Comes with a mount and Fastfire III for $600 (XTR-II is $800). I ordered this package, should come in the mail tomorrow...

ETA: with regards to .308, it's still worth looking at scopes designed for 5.56. Depending on your load, a lot of the drops are very close (or you could repurpose them for slightly modified ranges). Most manufacturers have a product sheet that will show how high/low .308 loads are going to be at the various BDC ticks.

BigJimFish:  I REALLY like the reticle design because of the mil-dot system and brackets.  I like how the reticle is not married to any specific barrel and round combination.  I just skimmed your post, but will read it in more detail when I get a chance.  The only thing that remains to be seen is how robust the scope will actually be.  It'd be nice if Leupy would pick up the reticle design.  GOOD JOB, brother.

Thus my comment above referencing Optisan as a, "cheap chinese optic"....







With cool names like mamba, viper, etc., these, the new 1-6x will be attractive to the shooter who fires 100 rounds a year who will give the new scope accolades. Serious users will avoid.

Hmm, well, I see your point, but just because they do primarily offer cheap scopes do you think that they don't have the capacity to build something of better quality?  Kinda like how Kia and Hyundai used to build shitty cars but now have significantly stepped up their game.

kia and hyundai still build crap cars...they are better than they were but still crap...

I have not purchased one of Primary Arms scopes but I plan to in the near future. From what I have seen and read they try to produce a quality product at a economical price. Are there scopes good enough to be slammed into barrels at 3gun matches? Probably not but not many amateur competitors would? I guess my point is they are also releasing a scope from Optisan with there reticle design. I don't think Primary Arms is going to put there name on a product that they feel is a POS. Yes I think there are much better quality scopes on the market but for a limited budget person like myself I think it could be a very nice product to get into and not brake the bank. Also It could help the market with some of the bigger companies. It could force them to lower prices or create a product that is in a more comparable price range.

 Lol.

A lot of scope companies have different tiers of quality.


Nikon
Leuopold
Bushnell
Burris
vortex

To name a few

       


















 
 

I have never understood why the manufactuers keep insisting on using 24mm objectives with these scopes.  Yes, it made sense back in the 1-3x days, but it started to fall apart once they started offering 1-4x scopes with 30mm tubes (7mm max pupil dialation x 4 = 28mm).  And gets really silly with 6 or 8x max magnification with ideal objectives of 42 and 56mm (plus isn't someone making a 34mm tube but keeping the 24mm objective for a 1-X scope).

I wondered the same about the front lens being to small and found a discussion on optics talk (can't find it now but...).  It has been my understanding that from an engineering and design aspect to have a larger objective lens the longer the scope must be to accommodate the light transmission within the scope.  This length restriction is magnified in scopes designed to go down to the 1 or near 1 power range.  For example, you can have a 40 or 50mm objective lens but the draw back is a scope that's 20 or 30 inches in length.

Of course the Leupold MK6 1-6x goes against the above logic and has a great eyebox with only a 20mm objective.

Elcan Specter TR 1/3/9x Shot Show 2014 Mini Review

The Elcan Specter TR is their answer to the 1-8x market. Just like the DR, it is unconventional in design. This time the design features 1/3/9x magnification settings that operate via a three-position knob located on the left hand side where the illumination control usually is. This knob turns with virtually no force. It is quite fast. Just as on the Specter DR, the zeroing on this scope is done with exposed adjustments on the base. While I was ok with this on the DR because it is a 1/4x primarily close quarters scope, I’m not a real fan on a scope that goes up to 9x. In general, 1-8x scopes have been for more than your 5.56mm AR, though they certainly work for that. Really, they are targeted at AR-10 variants, which incidentally, now exist even up to .338lm.  Miller Precision announced that variant at this years show though they only had the .300 Win Mag on hand to shoot on range day. What I am saying is that I expect to be able to use a 1-8x like a sniper scope, not just like a red dot. I want to be able to effectively dial even if the reticle is a hybrid design, which might actually be the best way to go.


Elcan Specter TR next to the reference Leupold CQBSS in a Bobro 34mm cantilever mount.

The reticle in the Specter TR is a BDC type reticle in what looks like the ACOG vein. However, it also sports windage holds. Given the lack of a real easy, comfortable, adjustment knob I am not sure how valuable these holds are. The reticle is in the front focal plane and is very bulky at 9x. The 9x pictures came out terrible so your just going to have to trust me on that one. As for the optics, they didn’t impress me in the way that the DR 1/4x did. The field of view was smaller then the CQBSS I used for a reference. Field of view and been class leading in the DR. Beyond that, the image was darker and yellower. While the resolution might be there, the overall experience was nowhere near the reference CQBSS. The Specter TR felt cramped at all powers and further displayed more pincushion distortion at 1x than I find acceptable even in a mid priced optic. Despite having dot bright illumination I do not expect that it will test very fast. While this optic was a first run and doesn’t have all the kinks worked out, it’s not a pure prototype and I don’t think the optical system and concept are really working. The MAP will be $3,194 and the earliest possible date for availability would be somewhere around midyear.


Elcan Specter TR through the scope at 1x.

Not to call out, but he has a long history of providing "matter of fact" reviews on products he has never owned.

My comments have been based on actual ownership or use of products owned by others at the range. We seen several optisan mamba's come thru our classes. In the end, it offered nothing more than a sub-$200 dollar optic offers and two did not make it thru the class. So when optisan announces a new scope, just because a member here designed a reticle for it, its still an optisan.
Of course fanboys of low end, cheap chicom optics will continue to rationalize their purchases and continue to spend on these ultra low end scopes thinking that one day these companies will produce a Nightforce equal optic for $199. My advice to them is save their money and get the real thing.


 

Summary: You have no experience with the Optisan 1-6.

I had a Mamba by the way. I don't recommend it, but it's not the same optic as the one you rudely replied about.