Optics Review: SIG SAUER TANGO6 5-30x56mm Rifle Scope

Optics Review: SIG SAUER TANGO6 5-30x56mm Rifle Scope

From the moment I first picked up the Tango6 5-30x56mm from SIG Optic’s Tualatin, Oregon headquarters, I knew I was going to like this scope. That was well over a year ago. I’ve now managed to put around 2,500 rounds of 6.5 Creedmoor downrange with the TANGO6 riding my Mausingfield, and here’s what I found.

To establish its optics division, SIG SAUER was able to lure away a number of executives and engineers from another Oregon-based optics company, Leupold. In short order, SIG rolled out some very impressive offerings, such as the Kilo 2400ABS rangefinder, the ROMEO4 red dot sight, the ECHO1 Thermal Reflex sight, and the Whiskey 5-25×52 hunting scope.  After a successful launch of a wide optics product line, SIG SAUER’s optics division has since expanded and is now based out of Wilsonville, Oregon.

While most of my scopes are from Leupold (30+) and Vortex (8), I have recently purchased a BRAVO4 4x Battle Sight, a ROMEO4, a Gen 1 TANGO6 3-18×44 for my Seekins AR-15, and a TANGO4 4-16×44 which resides on my Savage .22 Magnum.

Before getting started, it is worth pointing out that the 6 in TANGO6” is a reference to the fact that the scope has a zoom range of six times. This model runs from 5x to 30x.

When I unboxed the SIG SAUER TANGO6, the first thing I noticed was the attractive graphite gray finish. But I quickly focused on the details: at 15 inches, this scope is much more compact than my Schmidt + Bender PM-II, my Leupold Mark 8 5-25,  and my US Optics ER-25. The TANGO6 is a short, fast scope. But you pay a weight penalty for that compactness; the TANGO6 is 10 ounces heavier than the PMII. On mountain hunting rifles, for example, weight is going to be a critical. However, for most long-range precision shooting, it’s not a consideration.

Next, I noticed that the scope is made in Japan. Japan produces very high-quality glass these days. Even though I’d prefer to see scopes made in the USA, Japanese glass doesn’t disappoint. So let’s run through the scope point by point.

Turrets

The next thing that caught my eye was the distinctive and well-designed turrets. SIG has made a conscious effort to set themselves apart with distinctive visual styling ques which they have dubbed “Stealth ID.” As I understand it, this is an effort to introduce flat surfaces to optics where feasible, which pays homage to the F-117 Stealth fighter/bomber. Some of their other scopes, such as the Gen 1 BRAVO4 4x Battle Sight, take the concept much farther.

That may sound like just so much marketing hype, but I really like these turrets. They feature flat surfaces and knurling that reminds me of the classic 30-line per inch checkering found on many custom 1911 pistols.

This checkering works in combination with 1/8-inch-wide serrations to provide positive grip and good looks to boot. I might go so far as to say that the combination arguably provides the most well-designed tactile grip and visual appeal of any scope manufacturer to date.

But good looks only get you so far: function trumps visual aesthetics every time. Fortunately, many of the SIG SAUER engineers learned their craft at Leupold so they are no strangers to quality. But as an owner of a S+B PM-II, I have been forever spoiled by the knife-like sharpness of the “clicks” of that benchmark scope. Honestly, the clicks of my TANGO6 feel a bit mushy as compared to the S+B. And by that I mean that there is a slight bit of softness or mush between the clicks that is simply not present on the S+B.

Having said that, I don’t mean to overstate the criticism: most scopes outside that top tier have this issue to some degree or another. Nonetheless, it’s not a deal-breaker for me: I appreciate the fact that each click on the TANGO6 sends enough vibration through the turret such that that they are unmistakable – even with tactical gloves. Add to that an audible sound made by each click and the clear hash marks, it’s easy to precisely dial in your come ups.

Besides positive, precise clicks, one other critical issue when discussing turrets: whether they lock in some manner. Hunting scopes traditionally used caps to prevent inadvertent movement, but caps aren’t seen as a feasible option on a military or tactical scope.

Manufacturers have devised a variety of solutions to allow the user to “unlock” the turret for manipulation. SIG’s approach, which they have coined the “Lockdown Zero System,” features turrets that pop up and lock down via vertical movement.

This is by no means an original approach: my Bushnell DMR 3.5-21 uses this same design as do others. However, it is a proven technology that is both intuitive and fast.  What I really like is that if you’re in a competition environment, you can simply keep the turrets positioned in their “up” position and not worry about locking them down.

The turrets will stay in that “up” position on their own. On the other hand, if and when you want to lock down the turret, you just simply push down on the turret and you are good to go.

 

Just like my Leupold Mark 8, the turrets on the TANGO6 offer 12 mils of adjustment per rotation. That’s good because with most calibers, you will never need to go to the second rotation to reach out to the round’s maximum effective range.

By comparison, my US Optics has 11 mils per rotation, and my S+B PM II has 14 mils per rotation. The top-tier scopes such as the S+B and Tangant Theta manage to pack all of their rotation into two turret rotations, and have both visual and tactile indicators to tell you which of the two rotations you are on.

With the TANGO6 scope set on top of a 30 MOA rail, I have 19.5 mils of elevation available to dial up from a 100 yard zero, which is enough to theoretically get 6.5 Creedmoor out to 1600 yards (+/-). Nonetheless, if you want to shoot out past a mile, the SIG SAUER TANGO6 may not be the best option because it has less available turret adjustment than some other brands.

Power Ring

The power ring on the TANGO6 is a definite high point. The ring itself is wide, grippy, and easy to turn. It is very smooth throughout its entire range.

While it doesn’t come with a switch-lever type device, it really doesn’t need one. The raised zoom level indicator has two, green fiber optic tubes that make the dial easy to turn and easy to see. Here’s how it looks from the operator perspective:

My only suggestion for improvement would be to make the magnification numbers readable when you are behind the gun. Having said that, once you get used to the scope you can pretty much guessimate the magnification based on the position of the fiber-optic indicators.

Zero Stop

The “LockDown Zero” system is a stop-locking turret that allows a rapid return to zero. After dialing up elevation, the LockDown Zero system eliminates worry over how far to turn the elevation dial to return adjustment to zero. The turret not only stops at zero, it locks at zero.

The zero-stop feature is well designed and is relatively simple to set. It’s definitely a step up from shims. First, you zero the rifle. Next, you remove the turret, which is held in place by three 2mm hex set screws. Once the turret is off, the turret shroud can also be unscrewed via the same hex key.

Once the shroud is removed, you will see a brass-colored part that is held in place via three 1.5 mm set screws.   Loosen those three screws, and then turn that part clockwise until it stops. Hand tighten the set screws, and then replace the shroud. Finally, install and hand-tighten the turret such that “0” hash lines up with the hash marks on the scope. Presto. You are done.

Reticle

My TANGO6 came with the Dev-L Mil reticle, which is a Christmas tree style reticle. I own other scopes with very similar reticles, such as the Horus H-59 and the Vortex EBR-2C, so transitioning to the Dev-L was easy and intuitive. This reticle has many of the latest sought-after features, such as a .2 Mil center dot, .2 Mil elevation sub-tensions, multiple sizing ladders.

I found the sizing apparatus was very helpful for estimating the size of steel targets at distances out to 1200 yards. During a class I took back in May of 2017, I got a first-round hit on a known-size target at an unknown distance using the sizing apparatus – I was able to measure the target correctly at 900 yards and added 1 mil for windage. Clang!  What a great feeling.

Levelplex Anti-Cant System

One of the most impressive features of the TANGO6 is the “Levelplex” digital leveling system, which is an inclinometer-powered leveling display which appears in the outer edges of the reticle. This system obviates the need for a bubble level.

According to SIG SAUER, the Levelplex system is accurate to within a ½ of a degree in either direction. SIG SAUER claims that a bubble level is accurate to within three degrees. I’m not sure how they came up with those numbers, but it seems to me the practical accuracy of a bubble level is largely dependent on the operator’s attention to detail.

In any event, the Levelplex system works very well. Perhaps too well. It’s so damn precise that it’s actually a bit hard to get used to.

The biggest benefit is that you’re looking through the scope at the very moment you are making the final adjustment. With a bubble level, in most cases, you have to take your eye off the scope slightly to see the bubble.

At first, you can end up wasting a lot of time rocking the scope back and forth trying to find that narrow sweet spot. Because the sweet spot is so narrow, it’s easy to overshoot it. And then you get pissed because the damn triangle is nagging at you. You can overcome this with practice, and having a really smooth bipod helps as well.

Rather than try to make my own half-assed video showing you the levelplex, here’s one produced by SIG SAUER that shows you how it works.

Parallax Adjustment 

The parallax adjustment dial is located on the left side of the scope in the traditional location. SIG SAUER follows the recent trend in scope development which is to make that left turret a dual-purpose turret.

The inside of the turret contains the parallax adjustment dial, and the outer portion of the turret contains the illumination dial. I initially had problems remembering to only turn the inside dial when adjusting parallax; I would instead accidentally turn on the illumination. It’s a training issue that you eventually overcome. But it would be nice if SIG SAUER could design the turret such that the illumination can be locked in a manner that the entire turret dials parallax.

Illumination

Another high point on this scope is the illumination. It’s really the first illuminated reticle I have experienced which is truly daylight bright. Far better than my Leupold Mark 8. (Note: I found it difficult to photograph through the reticle, and my photos do not do the glass justice.)

Even better, the TANGO6 rifle scopes have a motion sensor feature which SIG SAUER calls “MOTAC.” After six minutes of rest, the illumination automatically turns off. When the motion sensor detects motion, it automatically turns back on.

I think this is a great feature. I always forget to turn off the illumination on some of my scopes, so I tend to have to change the batteries often. The SIG does the thinking for me in this regard.

Eye Relief, Threshold and Tunneling

With a 6x power range and a short overall length, I did not expect the TANGO6 to have an extremely forgiving eye relief threshold at 30x. I ended up being pleasantly surprised, and have found it to not be a problem at all. For most of my shooting, I back the power off to 25x in any event, and there, the eye relief threshold is even more generous.

I also appreciate the fact that the TANGO6 scope doesn’t give you that horrible tunneling effect that you get with less expensive scopes. It’s not in the same league as the Hensoldt in this regard, but its good enough to not be a problem.

Glass

Alright…let’s talk glass quality. This tends to be one of the major deciding factors when folks make the decision to shell out $2000 to $4000 on a rifle scope. Personally, I think accuracy and repeatability/durability of the tracking mechanism is a more important consideration for long-range shooting, but obviously it’s easy to fall in love with sharp, high contrast glass. Besides, these two factors tend to go hand-in-hand.

The TANGO6 uses two different types of glass. Some elements use high transmittance glass (HT), while other elements are made of extra-low dispersion (ED) glass. It seems that every manufacturer has a pet name for its glass; SIG has coined their “HDX.” SIG says that its glass has “industry leading light transmission and optical clarity” but offers no proof to sustain this claim on its website. I’ve perused the websites of all of the major manufacturers, and they all seem to make a similar claim, so that is what we lawyers refer to as “puffery”.

Unfortunately, glass quality (sharpness, contrast etc.) is subjective and hard to evaluate. With an “in service” date of 1967, my Army-issue Mark 1 Eyeballs may no longer be the most precision instrument on the planet. I wear glasses to correct for being nearsighted. Having said that, I own 50+ scopes and I have peered down virtually every major scope brand over the years, so I have had many opportunities to form an opinion on the topic.

I have come to the conclusion – as a general rule – that when it comes to glass, you get what you pay for. In other words, price generally tends to be a fair approximation of glass quality.

As an example, and despite what you might read on Facebook, I have never seen a $1000 scope which competes with a $3000 scope in terms of sharpness and contrast. Yes, it’s true that some scopes are more “warm” than others in the same price range, and some scopes may be more optimized for low light, etc. But there are no free rides when it comes to scope quality.

To test the sharpness of the SIG SAUER TANGO6, I didn’t do anything terribly scientific. I write my reviews from the perspective of the consumer, so I try to keep testing methodology simple and non-technical.

I posted various size print at 50 and 100 yards and compared the SIG SAUER to my Schmidt + Bender PM II 5-25, my Leupold Mark 8 3.5-25, and my US Optics ER-25 5-25. When comparing the scopes, I set the SIG to 25x to try to make it an apples-to-apples comparison.

Perhaps surprisingly, the SIG SAUER matched up well against the vaunted competition. In fact, I couldn’t detect any meaningful difference in sharpness, contrast, or resolution between any of the four scopes at resolving typeface at 50 and 100 yards.

I also attempted to test the ability of the scope to resolve details on objects located at 700 and 1500 yards. Again, I found no meaningful difference between the four scopes.

For example, setting all four scopes to 25x, I could not easily resolve the 1.75-inch tall words on a sign located approximately 700 yards from by deck of my house during low-contrast overcast conditions. The other scopes limited out a 25x, but since the SIG goes to 30x, I tested it at 25x when making head-to-head comparisons.

I was finally to able to partially read the sign with the SIG set to 30x. Backing the SIG back down to 25x, I could still barely read parts the sign (but now with the benefit of knowing what the sign said). I went back to the other scopes and again could barely made out some of the words.  I repeated this test multiple times on different days in different light conditions over a period of 6 months to see if the results remains consistent.  They did.

The S+B might have faired the worst in this regard, but again it was a close call. I’m not sure how often the extra magnification (i.e. from 25x to 30x) would provide a real-world benefit, but I could see it being important when trying to mil an unknown distance target or evaluate a distant deer or elk.

Tracking

Tracking is one of the most important features on a precision rifle scope. To test the TANGO6’s tracking, I created an 8-foot tall target board with one-inch hash marks. This target allows me to shoot groups at a 100-yard zero and with 20 mils added to the elevation turret.

The 20 Mil Target was placed exactly six feet above the zero target. During testing, I discovered that the elevation turret on the TANGO6 maxes out at 19.5 mils over my 100-yard zero, so I tested it to 19 mils instead of 20.

1 mil = 3.6 inches at 100 yards. So 19 mils of adjustment should raise the bullet strike 68.4 inches at 100 yards. My +19 mil 5-shot groups consistently measured 68.50 to 68.70 inches above the zero group. [Note: in the photo above the tape measure was indexed to the bottom of the board, which is one foot lower than the zero target].  I repeated this test 4 times over a 6 month window with consistent results.

This may represent a very small (0.15%) tracking error that I think is insignificant from a practical standpoint. It may also be within the margin of error for this type of field testing. Keep in mind that with my 6.5 Creedmoor reaches out to 1000 yards with less than 8 mils of elevation, and a typical .308 Winchester gets to 1000 yards with 12 mils +/-.

Having some lingering doubts about my testing methodology, I was able to take my scope over to the former SIG HQ in Tualatin (conveniently only 20 minutes away from my work) where I was able to place my T&E sample on testing equipment and verify that the scope was, in fact, tracking perfectly.

Conclusion

I’ve seen references on the internet referring to the SIG SAUER TANGO6 scope as a “second tier” scope, with the “first tier” generally reserved for marks such as Schmidt+Bender, Hensoldt, Tangent Theta, Nightforce BEAST, etc. The price point of the SIG, which is considerably less than those scopes, seems to confirm this assumption about its status.

Having said that, I’ve tested this scope for well over a year now, and I’m having a hard time thinking of this scope as being merely “second tier” for anything other than over-one-mile applications. I like everything about the TANGO6. If it’s truly second tier, then first tier seems like a diminishing return.

Running it side by side with my S+B, my U.S Optics ER-25, and my Leupold Mark 8, I don’t feel like I’m leaving much, if anything, on the table when I’m running the SIG shooting out to 1000 yards. The only areas that leave a bit to be desired are the higher-than-average weight and the fact that it only has 80 MOA (.23 Mil) of elevation. It does seem like it’s a step up from my Bushnell DMR 3.5-21 (which is a great scope for the $1,200 I paid for it), and two or three steps up from the Vortex Viper PST 5-25.

One last thing. SIG SAUER needs to up its game with regard to its website. There is simply not enough information on the website. Ditto for the manual, which refers you to a non-existent website “sigoptics.com” for “more detailed information on reticle subtensions.”

Specifications: SIG SAUER TANGO6 5-30×56
Reticle Options: MOA or MRAD, Dev-L or Milling Reticle in first focal plane.
Adjustment Value: 0.25 MOA or 0.1 MRAD
Adjustment Range (Elevation): 80 MOA or 23.3 MRAD
Adjustment Range (Windage):  46 MOA or 13.5 MRAD
Illumination Settings: 9 daytime, 2 night vision
Field of View: 20.2 ft at 5x, 3.4 ft at 30x
Eye Relief: 3.8 in
Exit Pupil: 8.8 mm at 5x, 1.9 mm at 30x
Weight: 42.05 ounces, as tested. (Manual says 39.5 ounces).
Length: 15.0 in
Tube Diameter: 34mm
Water Resistance Rating: IPX-7 (immersion to 1 meter for 30 minutes)
Caliber Restrictions: None
Other Features: HDX optics extra low-dispersion, high transmittance glass, Spectracoat, Lensarmor, Lenshield, MOTAC motion activated illumination, LockDown zero system, turret rotation counter, one free SIG Ballistic Turret
Warranty: 5-Year on electronic components, and “Infinite Guarantee” on the rest (“unlimited lifetime guarantee, fully transferable, no warranty card required, no receipt required, no time limit applies, no charge”)
MSRP: $2,999.99 (Milling Reticle); $3,119.99 (Dev-L Reticle). Current street prices are in the $2,100 to $2,300.00 range. I have occasionally seen these in stores on sale for as low as $1800.00-$2000.00.

 

Ratings (out of five stars):

Glass Quality * * * * *
There may be better glass out there, but you will be hard-pressed to notice the difference. You can spend a grand more and see little-to-no improvement.

Reticle * * * * *
I am a big fan of Christmas tree reticles such as the Horus H-59 and Tremor 2. The Dev-L reticle gives me the same features I like the “2-4-6-8-10” numerical markings, which make finding the correct holdover faster. For accuracy work, the 0.2 MOA center dot completely surrounded by 0.7 MOA of empty glass is the standard to beat.

Turrets * * * * *
The machining and checkering feel great, the clicks are crisp and precise, and the locking, zero stopping, and re-zeroing functions work just as they should. A free, custom BCD turret is pretty cool, too.

Mechanicals / Tracking * * * *
Tracking is the one thing that really sets high-end apart. My testing revealed that the TANGO6 does track almost perfectly at 19 Mils. However, 80 MOA (23.3 Mils) of elevation adjustment falls short of the modern norm at this quality and price level.

Overall Rating * * * * *
The TANGO6 5-30×56 is a very high-quality, solid optic with top quality glass, excellent function, good looks, and a killer warranty at a very competitive price. Some other brands offer more elevation adjustment, which may be important if you shoot out past a mile. But it’s as fine as anything you will find at its price point. The only scopes that may be “better” will cost you $1000+ more.