We realize that is has only been a couple of months since we reviewed the top of the line SIG Tango 6 tactical rifle scope, but we had the opportunity to get our hands on the next scope down from the Tango 6 and thought we should take it. We were favorably impressed with the Tango 6 and think that it is a solid offering, but this time around we want to see how one of their mid priced tactical scopes compares to even stiffer competition than what the Tango 6 has to face. The Tango 4 still offers some solid features, but there are significant differences between it and the Tango 6, as well as a significant reduction in the list price. For our review here, we brought in the 4-16x44mm with MOA knobs and MOA reticle for our detailed review and writeup.
Like on the Tango 6, one of the first things the proud new owner discovers when opening the box for the Tango 4 is that it is the same matte grey color as its Tango 6 cousin. Included in the nice box with the scope is a fine set of instructions, a certificate for a free SBT custom BDC turret from SIG, as well as the normal battery and Allen wrenches to adjust the knobs of the scope as well as set the zero stop. There is also a SIG SAUER labeled cloth included. The scope does not include a sunshade and includes only bikini style lens caps and not flip up scope caps, so those would be an extra cost item purchased separate from the scope. Like the Tango 6 line of scopes, the bottom of these scopes indicate that they are “Designed by SIG Sauer in Oregon” and “Assembled in Philippines”.
The ocular lens housing, otherwise known as the eyepiece, is the same large diameter setup as we found on the Tango 6 scope. This oversized eyepiece is larger than many other scopes and has an aggressive knurling on the power selector ring which further makes the eyepiece seem large. The eyepiece housing that holds the actual ocular lens has a nice rubber ring that extends a good quarter of an inch and is softer than most other scopes. This rubber ring has slight knurling on it to help the operator get a good grip to adjust the ocular lens, or dioptre adjustment. The ocular lens itself is a fast focus design that covers the entire dioptre adjustment range in 1.5 revolutions. It adjusts very smooth through the entire range of motion with moderate resistance. There is a small little lime green indicator mark on the outer rubber ring that can be used to track the adjustment location for different operators. When the ocular lens is adjusted all the way out there is no movement or slop which is a good indicator of build quality on a scope.
At the front of the eyepiece is located the power selector ring which again is the same setup as the Tango 6 scopes. The naming of the scope model actually indicates the number of magnification times that are available on the scope. Since this is a Tango 4, there is a range of four times on the magnification scale going from 4x to 16x. The Tango 6 goes from 3x to 18x, or six times. The power ring has the aggressive knurling as we have already mentioned and it provides a very good gripping surface in all weather conditions. There are two bracketing protrusions with two high-viz green dots on either side of the power selection indicator number that makes it very obvious what magnification the scope is set to. This protrusion is also used as a small throw lever to help with setting the power on the scope. The ring spans the entire 4-16x range in just less than half of the eyepiece circumference. The power ring is nice and smooth through the entire adjustment range with an even amount of pressure required throughout. The eyepiece is flat where the number markings are located, so they are not easy to see from behind the scope, though with a FFP reticle, it is not critical to know the exact power setting the scope is on at all times.
The eyepiece tapers down very sharply to the main 30mm tube and there is 1.9″ of space in which to mount the rear scope ring. The shoulder area of the scope is the same rounded shoulder that is found on the Tango 6, but the knobs are considerably different on this model. At the base of the exposed elevation turret is a half inch tall ring that has a clever rotation indicator mechanism to show precisely how many rotations from the bottom that the elevation dial is currently set at. The indicator goes from 0 to 7 and each rotation has 12 MOA of adjustment. At the bottom of the adjustment range there is a hard stop and the slanted white indicator mark is pointing right at the 0. Then as you rotate up through the full rotations the indicator mark rises precisely, showing exactly where you are at on the scale. It is clever and easy to use and clear see. This particular scope went 1.5 MOA past the final 7th rotation giving it 85.5 MOA of elevation adjustment. That lower ring around the bottom of the turret means the rotation part of the knob itself is quiet short with limited room for numerical markings so the numbers and hashes are short. There is some knurling at the top of the knob to provide some grip and it works well. Each of the clicks is firm with a precise semi-muted click. There is no slop between the clicks and there is a high quality feel to them. The top portion of the knob also has three set screws that can be loosened to slip the knob to zero once your zero has been set and there is a clever zero stop mechanism that we will discuss later.
The windage knob is similar in size and shape, though just a bit shorter than the elevation knob. The knob has a similar ring around the bottom but without the rotation counter and it has the same shorter rotational portion of the knob. The markings are again small, but still easily legible and the numbering counts up in both directions to aid the shooter in keeping track of adjustments. The knob also pops down and locks at the zero so the knob will not rotate without a conscious effort to pull the knob up and then rotate off of the zero mark. With the same 12 MOA of adjustment per revolution, the knobs begin to overlap at 6 MOA which gets a 308 Win 175gr load out to about 700 yards in a 10 MPH direct crosswind before the overlapping begins. Again, the clicks are very nice and precise with a good high quality feel to them.
On the opposite side of the scope we find a set of dual controls used for the illuminated reticle and for the adjustable parallax. The inside dial, the one closest to the tube, is the parallax control used to focus the scope. It is marked from 50 yards to 500 yards and then one final marking for infinity. The full adjustment range covers just a bit over half of the circumference of the dial and while the control is smooth through the entire range, it has a firm amount of resistance. The same aggressive knurling is on this dial as well to help with gripping it with just your finger tips. With the knob close to the tube and not having a lot of gripping area, the rough texture does come in handy for adjusting the focus.
On top of the parallax adjustment is the illuminated reticle controls which does have an off position between each of the ten brightness settings. This continues to be the preferred setup as it allows for the desired brightness setting to be chosen and then have an off right next to it, no need to go through all the other settings to get to the one you want. We do like the IR setting as well that is specifically setup for night vision use. There probably does not need to be as many of the really bright settings, but overall, it is a good mix and should work well. The illumination and parallax knob appears to be the same as is found on the Tango 6 and it can seem a bit large hanging off of the side of the scope, but is functional and effective.
In front of the shoulder area and the controls is another two inches of tube surface for mounting the forward scope ring. The scope then tapers up to the bell housing that holds the 44mm diameter forward objective lens. 44mm is almost considered small with modern tactical scopes and while a larger objective lens does help gather more light in low light conditions, the quality of the glass and lens coatings is far more important for light gathering. The smaller 44mm objective lens size allows the scope to be mounted lower to the rifle and additionally allows for a more compact and lighter weight scope. The bell housing has s black ring on the end with some interesting indentions, and while it is threaded, the taper to it does not appear as if they intend to offer a sunshade, which we still have not yet found for it or the Tango 6 scopes. This may eventually change.
As we mentioned in the beginning of this review, the anodizing is the now SIG Optics standard gun ship grey… well, they call it a matte Graphite. It is a distinguishing feature and it looks nice and is a high quality finish, but there is mixed reaction among users as to whether they like it or not. It does appear that SIG is going to be offering some black ones as well. The overall fit and finish is very good and when you compare the Tango 4 to the Tango 6, the outward appearance is very similar and they appear to share many, if not most, of the same parts. The internal mechanisms and the control knobs are different as well as the coating and glass quality, which all account for the price difference in the scopes. The Tango 4 has the SIG SAUER Infinite Guarantee which is a unlimited lifetime guarantee on the scope that is fully transferable and a clear indication of SIG’s confidence in their product.
All of the Tango 4 models have the reticle located on the first focal plane and our sample had their MOA milling reticle to match the units on the knobs making it a MOA/MOA scope. The reticle is a standard looking tactical reticle with hash marks used to indicate the number of MOA which can then be used for range finding as well as hold offs. The distance between each hash mark is 2 MOA and the reticle is open in the middle with a small dot at the very center to indicate the aiming point. As you go from the center aiming point out toward the edges, at two different areas, one half-way, the other at the end, there are little hash marks at 1 MOA intervals for even more precise measuring. The reticle is effective and nice and it is well sized to be effective at the max 14x and minimum 4x. When zoomed all the way out many of the details fade away as is to be expected. SIG also offers a few other reticle choices if the operator would rather a different alternative.
The optics themselves appear to be quite good and very competitive against other scopes in the same price point. The scope picture is bright with good contrast and sharpness all the way out to the edges. We could not find any real faults with our use of the scope and its optical capability. The fast focus eyepiece allowed us to quickly focus the reticle and the parallax adjustment worked as expected allowing us to get a sharp image at the various ranges we used the scope. The focus is limited on the bottom end to 50 yards so if you were needing a short range air rifle scope, this would not be an option, but for long range tactical work it is not an issue.
For our practical testing we mounted the scope on our trusty Remington 700P test rifle that we have used for a good number of tests. We used a set of Leupold Mk4 30mm medium height rings to mount the scope, which is about as low of a ring as you can find, and there was still plenty of room for the bell to clear the barrel of the rifle. Being able to mount it low meant our cheekweld was good right off the bat as we had a TacOps cheekpad already attached which provided a little bit of elevation for our cheek. The rifle is a short action 308 and has a Warne 20 MOA single piece canted rail, so mounting the scope was very simple with ample ring mounting options. Our primary shooting day was conducted on a cloud covered 42 degree (F) spring day with a slight drizzle.
All of our shooting for the practical test was performed using a sandbag up front and a sandsock at the rear of the rifle to aide in accuracy. If you are not familiar with our scope testing procedures, please take a moment and ready our article on how we test rifles and scopes. After our initial zero, which involves a bore sight and then a single 25 yard shot for adjustments to get us on paper at 100 yards, we began our box test to check the repeatability of the control knobs. The box test checked out excellent, which we have mentioned before is typically a routine test for modern scopes. But the 20 MOA adjustment size test is one that has been more difficult for scopes to pass. We fired a group, dialed in 20 MOA of left, fired another group, and then dialed in the 20 MOA of right back in to verify the adjustments have moved back to the original location, which they did with good results. The groups of the rifle were right at .75 MOA, which is a bit larger than we normally like and would introduce a little more potential error in the final results. When we measured the distance between the groups they measured 21.2″ apart. 20 MOA at 100 yards is equal to 20.94″ which means we saw 1.2% of error in the adjustment size. We consider anything under 5% to be a passing score and 3% or better to be considered a good score. The results with the Tango 4 were very good even with the larger group sizes fired from the rifle.
Our final two operational tests that we perform on the scope are to check for reticle drift while going through the entire zoom adjustment range as well as the parallax adjustment. This is measured using a grid style boresighting device mounted to the muzzle of the rifle. We align the reticle with one of the grid points and watch for drift while adjusting the scope controls. These two tests are hard for many scopes to pass, especially for lower quality scopes and even some higher quality scopes. With the zoom test on the Tango 4 the reticle was very solid and we were not able to detect any reticle drifting at all and were very pleased with the results. We next went to the parallax adjustment test and were again impressed with no perceptible reticle movement through a vast majority of the focus range. We thought we may have noticed a tiny bit of movement from the 60 yard down to 50 yard area of the knob, but it was so small it would not matter at those ranges. By keeping the bottom end of the parallax adjustment range at 50 yards, it undoubtedly helped the scope on this test. Often we see the big reticle shifts when the parallax adjustments go down to 25 yards or even closer. Overall, the performance was very good on these two tests.
As we were performing our tests with the scope we noticed that the short knobs perched up on top of their tall towers did have a slight left-right wobble if you pushed on them. It did not seem to effect the performance of the scope or knobs, but it was a enough for us to notice and figured we should mention it here. This appears to be from the zero stop style functionality of both the windage and elevation controls and how the zero detente functions. On the windage knob when the knob hits zero, it drops down into a locked detente position which is nice to keep them in place. You then have to pull on it and then twist in order to dial in adjustments. It is then that you can detect the slight wobble. The elevation knob also has a zero stop feature that is a little bit of a hassle to set (most zero stops are) but once done is a clever setup. When the zero stop is set the elevation knob has the same detente in it as the windage knob does, but it is only there for your initial zero. If you go a full revolution past it will not drop into the detente at zero like it does where you set your zerostop. When it is in that detente, you have to lift it just like the elevation knob to begin dialing in adjustments. With the zero stop set, there is also a hard stop beyond the detente to make it absolutely clear that you are at your zero.
Looking at the Tango 4 scope there is a lot to like. In fact, what you are giving up versus the Tango 6 is not much. Some additional magnification range and perhaps some better knobs, but performance wise, the little brother seems to hold its own and makes a case for choosing it. The faults are minor and we certainly would like to have a sunshade option available, but this is a very good scope for the price point and should do well on a tactical rifle. More MOA per revolution, taller marking area for the knobs and some other nit-picky things are things that can be lived with. Some may not like the turret design either, but they work and there is even that option for the free BDC turret, which only has markings for two rotations, or 24 MOA which doesn’t get out too far with a 308, about 750 yards. But overall, this scope offers a lot for the price and SIG is firmly standing behind it with its warranty. If the features meat what you are looking for, we certainly cannot find many reasons not to recommend it.