Sep 302016

written by ILya Koshkin, September 2016

High End Tactical Part V: The Cruiserweights

I called the previous High End Tactical article “The Heavyweights” and figured I can stick with the martial arts analogy for this one.  Since the scopes I am looking at are a bit smaller, I figured I can call it “The Middleweights”.  

After some reflection, it occurred to me that the name is not really very appropriate.  This will meander a little, but since I plan to continue looking at high end tactical scopes for the foreseeable future, I figured a little meandering is OK.

As a matter of background, I have been a martial artist most of my life.  I am a pretty big guy, so I am certainly a heavyweight; however, the weight classes I enjoy watching the most, be it in boxing or MMA are the middleweights.  The lightweights may be faster and more technical, but they are usually not big hitters.  The heavyweights hit harder, but they seldom have the speed and as far as technical ability goes, the heavyweight fighters are usually the least skilled of all weight classes (there are exceptions, of course).  The middle weight classes is where you have guys who are extremely technical while still being big enough to hit hard.  To me the middleweights are the best overall fighters in the sport.

Well, the scopes I am looking at for this article are kinda like that: they are exceptionally good allround and can do almost everything in a pinch.  

I was going with the whole middleweight theme until I actually spent some time with these scopes and realized that in terms of “punching power” (to continue with martial arts analogies) these scopes are dangerously close to the larger designs I called “The Heavyweights” in the previous article.

The Middleweights really should be scopes with objectives in the 42mm range and a magnification range of right around 2.5-10x or thereabouts.  For example, Nightforce NXS 2.5-10×42 would be an example of such a scope.  Of the scopes I have assembled, only Leupold Mark 6 3-18×44 and Nightforce ATACR F1 4-16×42 could conceivably qualify as middleweights, but both of these sorta punch above their weight class.  

Truthfully, if I manage to finally convince someone to make me a FFP 2.5-15×36 with David Tubb’s DTR reticle, weighing less than 20oz, that will be the perfect “Middleweight” the way I see it

With that in mind, I renamed this article into “The Cruiserweights”.

Still, with all that, there are really a few distinct parts to this article:  Nightforce ATACR F1 4-16×42 and Leupold Mark 6 3-18×44 go head to head.  Sig Electro Optics Tango6 3-18×44 also goes head to head with them.  I received the Sig later than others, so I have not had as much time with it and while I will occasionally mention it here, it will largely be a subject of another article.  They have smaller objective lenses than the rest of the scopes here and both seem largely designed for the same application.  Tangent Theta, Steiner M5Xi and Minox ZP5 are similarly priced and have the same basic configuration in terms of magnification range and objective size.  These three offer a very “clean” comparison.  That leaves Steiner T5Xi,  Vortex Razor Gen II and Kahles K312i as different approaches to the same basic value problem:

  • Steiner T5Xi is significantly cheaper than every other scope in this test, so it is an entirely different value proposition.  Here, the question is really “what do you give up by paying $1k less
  • Kahles K312i is also on the lower side of the spread in this group in terms of price, but it has a different take on user friendliness and on optical optimization.  It does have the lowest top magnification in this group, so that is a part of the compromise
  • Finally, Vortex Razor Gen II is the company’s most ambitious design yet with Vortex flatly stating that they are willing to compete against anyone else out there  

Here is a spec table for the scopes I have assembled here:

F1 4-16×42
Mark 6
Razor HD Gen 2
30 (31.9 w/caps)23.629.8 (31.5 with sunshade)46.5
3.35 – 3.543.8 – 3.93.5 – 4.33.7
26.9 – 6.9




36.8 – 6.3




36 – 7.3




37.8 – 6.25



Exit Pupil, mm10.3 – 2.7 12 – 3.4 
Click Value0.1 mrad0.1 mrad0.1 mrad0.1 mrad
Adjustment rangeE: 26 mrad


W: 18 mrad

E: 29 mrad


W: 14.5 mrad

E: 34 mrad


W: 15 mrad

E: 35 mrad


W: 20 mrad

Adjustment per turn12 mrad, double turn10 mrad, double turn12 mrad, double turn10 mrad, triple turn
Zero StopYesYesYesYes
Reticle LocationFFPFFPFFPFFP
Reticle IlluminationYesOptionalYesYes
Price$2400$2200 – $3200$1800$2200

Looking at the numbers tells an interesting story.  As always, they do not tell the whole story (that is why we test scopes), but they are worth looking at.  



Tangent Theta TT315M


Kahles K312i
Minox ZP5
Length, in14.213.814.813.6
Weight, oz32.5 (33.6 w/caps)27.7 w/caps29.532.5
Main Tube Diameter34mm30mm34mm34mm
Eye Relief, in3.5 – 4.33.543.543.54
FOV, ft@1000yards39.7 – 7.9



38.4 – 8.1



41 – 11.5



38.4 – 8.1



Exit Pupil, mm10.4 – 3.3311.5 – 3.59.7 – 4.211.5 – 3.5
Click Value0.1 mrad0.1 mrad0.1 mrad0.1 mrad
Adjustment rangeE: 26 mrad


W: 12 mrad

E: 18 mrad


W: 12 mrad

E: 26 mrad


W: 12 mrad

E: 28 mrad


W: 12 mrad

Adjustment per turn15 mrad, double turn6 mrad, double turn14 mrad, double turn15 mrad, double turn
Zero StopYesYesYesYes
Reticle LocationFFPFFPFFPFFP
Reticle IlluminationYesYesYesYes

Leupold Mark 6 is a seriously compact scope.  I put this spec table together prior to requesting the scopes from the makers.  When I first looked at the dimensions of it I thought that they must be sacrificing some performance for that compactness (I was right, and for some applications it is a worthwhile compromise, but more on that later).  As far as size and weight go, it is in the league of its own in this group. The next lightest is Tangent Theta TT315M, but it is two inches longer which is a big difference.  Nightforce ATACR F1 is designed to compete against the Mark 6 and it is almost as short, but significantly heavier.  Weight-wise it is right in the same ballpark as the 50mm designs.  Interestingly, Steiner T5Xi with its 50mm objective weighs about the same as the Nightforce and is barely half an inch longer.  Generally, both Steiners, Tangent Theta, and Minox are all of very similar weight and size. Kahles weighs about the same, but is the longest scope here.  Vortex Razor HD Gen 2, while a touch shorter than the Kahles is in an entirely different class as far as weight goes.  It is a full pound heavier than most scopes here.  Gen II’s weight has been a subject of considerable discussion ever since the scope was released and my take on it is very simple: if you are mounting a scope on a heavy precision rifle that weighs fifteen pounds to start with the extra weight of the Gen II is irrelevant.  However, if you are scoping an accurate gas gun that weigh 8lbs (like my Grendel chambered AR), it is a different ballgame.

Kahles has a seriously wider field of view (FOV) than everything else.  That is sorta their thing and it stands out.  However, on the flip side of the coin, K312i has the lowest magnification range here.  I did not feel particularly affected by it, but for some conditions it can make a difference.

Also, if you look at FOV, you notice that Tangent Theta TT315M and Minox ZP5 3-15×50 have absolutely identical numbers (same for eye relief).  Both are descendants of the original Premier Heritage 3-15×50 design and they bear certain similarities.  

Steiner T5Xi is the least expensive scope here and by a significant margin.  It also has the narrowest FOV.  I suspect that the narrower FOV is a side effect of trying to stay on a budget.

The next differentiator in terms of specs is the amount of adjustment and adjustment per turn.  Minox ZP5 and Steiner M5Xi offer the most adjustment per turn at 15 mrad, Kahles is not far behind with 14 mrad, T5Xi and Nightforce offer 12 mrad per turn, while Leupold and Vortex go with the somewhat common 10 mrad.  Tangent Theta here sticks out by offering 6 mrad per turn in a double turn turret.  All of these offer at least a double turn turret (triple for Vortex).  What this means is that with Tangent Theta, once you have everything set-up, you get 12 mrad of available adjustment.  If your shooting routinely requires more than that (mine does not), TT315M is not optimal for you.  You can get away with it by combining the reticle with the turret, but for ELR, I would look elsewhere, namely at the Razor HD Gen II with the most available adjustment in this group by a significant margin. As far as Tangent Theta goes, they do offer a larger version of the 3-15×50 design called TT315P with more adjustment.  However, it is more expensive and of less interest to me, so I stuck with the 30mm tubed TT315M.

All of these scopes offer a ZeroStop of some sort and reticle illumination. Most offer some sort of a locking turret arrangement, which I generally like.  However, for me zero stop is more important than a locking turret on scopes of this type (on smaller scopes where I am more likely to just use the reticle, I really prefer the turrets to either have covers or to lock in place).

In my opinion, scopes in this price range should have reticle illumination.  Note that I list two prices for the Leupold Mark 6.  It costs $2200 non-illuminated and $3200 with illumination.  From a consumer standpoint, paying an extra grand for reticle illumination is, frankly, preposterous.  I suspect that the pricing is set up this way because of some government contract.  If you do business with the US government, you can not offer the same product for sale to someone else for less than the government pays you.  I suspect that the price of the illuminated Mark 6 is set by some contract with the government.

Why do I spend so much time on size and weight of different scopes?  If you only shoot from the bench or prone, it may not make much difference for you.  However, when I test scopes of this type, they spend a little time both on my heavy precision rifle (Desert Tech SRS) and on a couple of lighter rifles (an 8 lbs 6.5Grendel AR-15, a 10 pound LR-308 and occasionally some others).  Once you get into this class, overall performance is not that different between most scopes, unless something gets pretty screwy.  Barring some serious QC problems, there are very few scenarios where I could take a shot with one of these scopes that I can not take with the rest of them.  It does not mean there are no differences.  They are there and they are noticeable.  However, with these scopes we are clearly in the “diminishing returns” part of the price range.  

Here is a spec table for the sub 50mm objective scopes.  I threw the Steiner T5Xi in there because it is comparatively inexpensive and rather compact for a 50mm design.

 Nightforce ATACR F1 4-16×42Leupold Mark 6 3-18×44Sig Electro-Optics 3-18×44Steiner T5Xi 3-15×50Bushnell Elite Long Range Hunter 4.5-18×44
Length, in12.611.915.313.114.2
Weight, oz30 (31.9 w/caps)23.631.829.8 (31.5 with sunshade)26.5
Main Tube Diameter34mm34mm30mm34mm30mm
Eye Relief, in3.35 – 3.543.8 – – 4.3 
FOV, ft@1000yards26.9 – 6.9



36.8 – 6.3



35.3 – 5.9


10.62 @ 10x

36 – 7.3



23.5 – 6


10.63 @ 10x

Exit Pupil, mm10.3 – 2.7 11.4 – 2.412 – 3.49.2 – 2.5
Click Value0.1 mrad0.1 mrad0.1 mrad0.1 mrad0.1 mrad
Adjustment rangeE: 26 mrad


W: 18 mrad

E: 29 mrad


W: 14.5 mrad

20.9 mradE: 34 mrad


W: 15 mrad

24 mrad
Adjustment per turn12 mrad, double turn10 mrad, double turn8 mrad, double turn12 mrad, double turn10 mrad
Zero StopYesYesYesYesYes
Reticle IlluminationYesOptionalYesYesYes
Price$2400$2200 – $3200$1800 FFP


$1700 SFP


I am not going to go through the whole forensic analysis again, but note how much longer Sig and Bushnell are than the other three scope in the table.  Price-wise, Sig is most directly competes with the Steiner T5Xi, with Bushnell providing some pressure from below.   Here is a picture that shows the comparative size of the Sig, Leupold and Nightforce:

I will have a separate section on each scope as I go along, but first here are some notes on how I test things and how the scopes compare.  Generally, I do not write up my methods in a whole lot of detail for a few reasons.  Mostly, I am lazy and I think my time is better spent by writing about scopes.  Second, that is more trouble than I am looking for. Bottom line is, that nothing that I do here is rocket science.  I am a fairly experienced observer and I am very careful with how I set up my experiments.  It is easy to do for anyone with basic understanding of experiment setup and rudimentary optics.

For optical evaluation, I simply look through the scopes side by side under a variety of lighting conditions and look for differences.  I have to make sure my eyes get enough rest and that the conditions change slowly enough for the comparison to be relevant.  I pay attention to spectral content of light sources since it can change considerably.  I do the same comparison multiple times.  I look at both test targets and real scenes (more real scenes than test targets).  If I find something really screwy or unusual, I set the scope up behind a collimator, take some images and do some numerical analysis.  

One thing worth noting is that the good folks at Kelbly’s sent me their fixture for mounting multiple scopes side by side  on a tripod.  They made the fixture when they were distributing March scopes and I inherited it.  That also gave me an opportunity to play with Kelbly machined rings and I am very impressed with how superb they are especially considering their light weight.  Generally, if you are looking for an accurate rifle, Kelbly’s is worth a look.  I am considering having them build me one.

For tracking and other mechanical tests, I do a few things.  Generally, there is no substitute to actually using these things the way they are supposed to be used.  That is one of the reasons everything takes me so long.  I go and use this stuff.  Tracking is tested both on a rifle under recoil, and in a fixture.  What I do with a fixture is a little different from the approach that has become so popular in the last couple of years, where people bolt the scope to a platform, point it to a grid target at a known range and see how the adjustments work.  I have a precision optomechanical tilt stage from Newport bolted to a tripod sturdy enough for me to sit on (it is the type typically used for pretty serious astronomical telescopes).  The stage is accurate to about a hundredth of a mrad, so it is more repeatable than typical 0.1 mrad turrets.  All I have to do is point the scope at an easily discernible spot fairly far away (like a corner of a building) and by manipulating the tilt stage and the turrets, I can easily test how the adjustments work and the reticle feature size.  I do not need to worry about seeing small features on a grid, about inclination of the line of sight or about distance to the target.

As I test things, I take fairly copious notes.  It can be problematic in low light since to be able to write something down I need light which messes with my night vision.  Sometimes I dictate, or use a red light.  Naturally, if someone else is looking at the scopes, I take notes which is easier.  Here are excerpt from my notes, just to show what they typically look like and what kinds of things I am looking for:

Low light test at around midnight looking out from the upper deck.  I am the observer. Examine the church at 757 yards (LRF’ed) with a single bright light that can be moved within the FOV.  Then look out toward the valley (city lights a few miles out).

Scopes tested are Nightforce, TT, Kahles, Leupold, M5Xi, Steiner M, all set on 10x.

Optically, under these conditions, Tangent Theta is the best in this group.  Kahles trails it very slightly. TT has a touch more contrast.  Both have very good flare control.  Ultimately, wide FOV is a big advantage in low light and these two scopes have the widest FOV in this group.  Neither is particularly susceptible to flare or ghost images.

The two Steiners: M5Xi and old M perform well, but have just a little more flare and stray light.  They perform very similarly to each other with the the old M showing a little more detail all in all than the newer M5Xi.  The two smaller objective scope, predictably were a touch worse since they had less light to work with.  In terms of overall performance in low light, the two do very similar things at 10x.  Leupld reticle is easily the most visible in low light in the group.  Nightforce and TT really benefit from illumination.  Kahles and M5Xi also need illumination; thick bars are OK but thin center practically disappears.  Interestingly enough the G2B in the original Steiner Military does better in low light.

Day light test.  Alex is the observer.  Impressions on TT, Kahles and two Steiners (M5Xi and Military), with the Vortex added in later.

First impression is at 10x, than 12x.  Primary observation target is a church at a lasered 757 yards.  Sun was at 3 o’clock.

TT stands out as having tremendous depth of field.  Everything (almost) is in focus, to the point where it can even be a little distracting.  Vortex also has extremely deep depth of field.

Kahles picks up a lot of mirage for some reason.

Kahles has the better detail in the shadow than Vortex and marginally better or equal to TT

Kahles image has a flatter look to it.

Ultimately, there is less pop in the Kahles image, but more color detail in the dark portions of what you see.

Steiner M5Xi is easily the least favourite for Alex.  He saw a lot of chromatic aberration that he could not dial out.  He liked the old Steiner M 4-16×50

Ability to see detail: TT, Vortex = Kahles, Steiner

Contrast: Too close to call

Flare: All are well corrected except for Steiner M5Xi that picked up some artefacts.

Adjustment feel:  TT and Kahles were the best in this group of 50mm scopes.  M5Xi the worst.  T5Xi and Vortex are close with T5Xi clicks a touch more distinct.

Another night time test.  First at high mag just for the heck of it.  I set all scopes to 15x.

Primary observations targets are the church and DeSoto.  Looking at the billboard behind Kaiser is interesting.

In terms of eye position flexibility at high mag, Steiner M5Xi was clearly the better scope here although none are bad.  Amazingly, both the Leupold and Nightforce can almost hang with the bigger scopes here.  Vortex appears to have the brightest image in this group, but in terms of retained contrast Tangent Theta is a little bit better (and so is Kahles).  T5Xi is very good and amazing considering the cost.

M5Xi seems to have a touch more contrast than T5Xi.

In terms of flare, M5Xi is showing a little more than others, but all are pretty good.  Vortex has phenomenal flare control for such a short objective system scope.  Tangent Theta and Vortex are similar in this regard.  Nightforce, Leupold, and T5Xi are just a touch worse and M5Xi is a little worse still.  I have seen a few M5Xi scopes and this one has more noticeable flare than others.  I wonder if this is just sample variation.

Either way, off axis light sources do not have a strong effect on any of these scopes.

At 18x, Leupold and Vortex both offer a lot of detail, but Vortex edges ahead, probably due to its 50mm objective.  The image is more contrasty.  Mark 6 image at high mag is a little dull.

Nightforce at 16x in low light easily hangs with Leupold and beats it slightly (in low light).  Leupold and T5Xi have slightly narrower FOV than most others and in low light at high mag there is a small perceptual difference in collected light.

At 10x, I can’t help but be impressed with the whole group.  Once my eyes are properly dark adapted, the smaller objective scopes suffer a little bit, but even with a 42mm objective, 10x is a viable magnification setting for a low light shot when the scopes are this good.

As magnification drops, FOV opens up and Leupold starts picking up more significant flare from bright source near the edge of the FOV.  M5Xi, oddly, feels a little less flare prone once the magnification goes down.  Older Steiner Military 4-16×50 that I have also has this effect.  Overall order of things is about the same.  Vortex, for what it costs is stunning.  TT is the best scope here in terms of glass, but it is also one of the more expensive ones.

Playing with the reticle illumination a few things jump out.  T5Xi does this really well.  a small center portion is lit: enough for some holdover, but clearly designed to draw your eye to the center.  Vortex illuminates the whole grid and I do not like it too much.  Nightforce illumination is too bright in really low light even at the lowest settings.

Going to 6x and lower settings is, to quote a movie I like, “Everything is illuminated”.  All scopes look excellent.  As FOV widens, it is easier to induce some internal stray light issues.  Nightforce and Vortex are impressively well-baffled for those.  I can induce some effects with Leupold as well, but they are not too well structured. With TT and both Steiners, by going way off-axis I can induce a semi-circular ghost near the edge of the FOV.  It is a sufficiently minor effect to not matter, but these scopes are so good I am left to nitpick.

If I am typing notes up as I go along, I use complete sentences.  Handwritten notes are naturally more terse.

Do keep in mind, that this is just a sample of the notes.  These same observations have been repeated multiple times.

The way these scopes line-up is sorta interesting.  Here is my aggregate assessment:

Optical quality in good light:

TT315M > Minox ZP5 > Razor Gen II ≥ ATACR F1 ≥ Kahles K312i ≥ T5Xi ≥ M5Xi ≥ Mark 6

Optical quality in low light:

Kahles K312i ≥ TT315M > Minox ZP5 > Razor Gen II ≥ ATACR F1 ≥ M5Xi ≥ T5Xi ≥ Mark 6

Depth of field:

TT315M = Minox ZP5 > Razor Gen II > ATACR F1 > M5Xi > Kahles K312i ≥ T5Xi > Mark 6

Flare control:

TT315M = Minox ZP5 = Razor Gen II = ATACR F1 = Kahles K312i ≥ T5Xi ≥ M5Xi ≥ Mark 6

Overall, Tangent Theta is exceptional and Minox is not far behind.  Kahles edges them both out in low light, but by a small margin. Mark 6 has some compromises built-in in an effort to make it as small it is.  Optically, it is a little behind other scopes here, but If you account for how compact it is, the fact that it hangs in this group at all is impressive.  I was extremely surprised to find that overall Steiner T5Xi was able to hang with its much more expensive stablemate the M5Xi.  In low light, M5Xi’s wider FOV helped, but in good light, I actually preferred the less expensive Steiner Tactical.  I have seen several Steiner Military scopes ever since the first ones came out and they all have some sensitivity to flare as the magnification gets past 10x or so.  I suspect that the sample I have is a little worse than average.  Once again, keep the context in perspective: these are all excellent scopes and I am nitpicking.

As far as mechanical quality goes, all of these scopes held zero.  I saw very little reticle hop with side focus adjustment (and that is not an easy measurement to make anyway).  In terms of tracking, the scope I spent the most time on was the T5Xi since there was a lot of controversy around it and the one I have tracks well.  I checked with Steiner and they made a design tweak that resolves the turret issue a number of early scopes had.  

I did check all of the scopes I had on hand and the only one that gave me fits was the Mark 6.  The version I have has the original M5B2 “squeeze to unlock” turret and I am not a fan of it.  

Adjustments were off by a considerable margin and each elevation turret setting had slop to the tune of ±0.1mrad. I do not think any of this is a secret to Leupold and the newer M5C2 turret is much better.  Generally, I think Leupold has some interesting things coming up in the Mark 6 line.  

As far as feel goes, there was a lot of difference between different scopes here.  Tangent Theta has easily the best click feel of any of these.  That should not be any sort of a surprise since it is 6 mrad per turn allowing for rather wide click spacing in a compact turret.

Mark 6 click quality as I mentioned before did not impress me.  Nightforce ATACR F1, on the other hand, is excellent.  The turret is low and wide, which I like and looks very much like the M5C2 turret on Leupold scopes. The turret is locked at its zero position and a push of the button allows it to move.  When you get back to zero, it automatically locks in place.  The turret does not lock in any other position other than the zero setting.  The turret feel of the ATACR F1 and Razor Gen II was somewhat similar in terms of ease of use, but the Razor Gen II can be locked in any position.  There is a collar that pops up to unlock the turret and can be pushed down to lock it in place. I think the clicks on the Gen II are very well weighted and the adjustments were dead on reliable.  It also offers three turns with a tactile indicator of which turn you are on.  However, in order to make that lock ring work, there must be some minimal play in the turret and the clicks on the Vortex are nicely tactile, but not as audible as T5Xi for example.  Of the high adjustment per turn designs, Kahles was the best one.  I am not a huge fan of turrets that allow that much adjustment per turn since the clicks end up too close together.  The best turret of this type I have ever seen was on the larger 34mm tube Tangent Theta and Kahles is up there as well.  Minox is quite good, but not as good as Kahles.  

Minox did something interesting with the markings on the turrets: they are freakishly white and visible.  Apparently they use some sort of ultra high reflectivity paint, so they stand out really well.  At a zero position, two triangle vertices are pointing toward each other.  It is hard to miss:

Steiner M5Xi turret, while adjusting reliably, had much worse feel and it was very easy for me to accidentally skip a click or two.  With visual verification, it worked fine and I did not have any tracking issues with it (I have tested a few M-series Steiners over the years and they all worked well, but the clicks were softer than I like).

Steiner T5Xi turret was more to my liking.  The tactile feel was a touch more “ratchety” than on the Razor Gen II, but more audible.  It was better than on the M5Xi all round.  The clicks are both tactile and audible and very usable.  They are a touch lighter than I like, but I had no problems getting used to them.  The spacing also feels a bit wider than on the M5Xi.  Another reason I was not too happy with the M5Xi turret is that it is quite tall which is not my favourite thing.  That is a personal preference though.

Last comment I’ll make on this is that all other things being equal, how wide the clicks feel is a function of how many clicks per turn are there and of how large the diameter of the turret is.  I tend to prefer turrets that are low and wide specifically for that reason.  It is worth keeping in mind that the clicks on a 10 mrad per turn turret can feel less spaced out than those on a 15 mrad per turn

With that commentary out of the way, here are some thoughts on each scope.

Tangent Theta TT315M is the only design here with a 30mm maintube.  That limits the overall adjustment range a little, but makes the scope a little lighter.  The turrets are also quite compact and designed to have no more than 12 mrad of elevation available after a proper zero using a 20MOA canted base.  12 mrad is sufficient for most of the shooting I do, but it is definitely not enough for those who shoot really far out.  For ELR, you need to step up to the more expensive 34mm models within the Tangent Theta line and I think that the higher magnification 5-25×56 TT525T is the better suited design.  Those 12 mrad on TT315M come courtesy of a double turn knob.  With 6 mrad per turn, the clicks are widely spaced despite a more compact turret than others here.  The click feel is just spectacular and tracking is flawless.  Another thing that is spectacular is the image quality.  In terms of overall optical quality it is the best scope here.  It is based on the original optical design of Premier Heritage 3-15×50 which I am well familiar with; however, it looks like something was improved.  There were a couple of artefacts inherent to the erector system design in the Premier that I do not see in the Tangent Theta.  Color is exceptional.  There is a lot of texture to the image and small details really pop out at you.  Depth of field is very deep which let me see the conditions at a good range of distances without messing with sidefocus.  Also, if I wanted to get a quick shot off, I could leave the sidefocus set for around 100 yards and the depth of field is sufficient to see everything from pretty close to a few hundred yards without struggling for image focus.  It does not mean there was no parallax error, but the image was sharp over a great depth.  The only complaint I have is purely subjective.  While I really like the Gen 2 XR reticle, I would have preferred the thick outer bars to be a little thicker.  As it is, at lower magnification, the reticle is very hard to use in low light without illumination.  Even in good light, it is not as fast to acquire at 3x as I would like.  This is a personal idiosyncrasy I have: I prefer to be able to use the reticle at all magnifications even if the battery has died.  Also, I really liked the fact that the windage turret on some scopes either has a cover or a turret lock (both Nightforce ATACR F1 and Mark 6, for example have simple covered turrets for windage).  I seldom adjust for windage, so that is a turret I do not use for much of anything aside from zeroing in.  I think for the TT315M a covered turret would save a little more money and fit into its overall concept better.  Also, as I mentioned earlier, this is a comparatively light weight scope (second lightest in this group after the Mark 6), which extends its usefulness to a broader range of rifles than that of a heavier scope.  Had I been in the market for a scope in this price range, the TT315M would be at the top of my list.  This is not just me trying to say the politically correct thing to maintain a good relationship with the manufacturer.  If I were planning to spend $3k on a riflescope for the shooting that I do, I would buy this scope.  I hope that is a blunt enough way of saying how much I liked it.

Kahles K312i in many ways stood out from this group as well.  This is an interesting scope because the basic specs do not look all that impressive outside of the really wide FOV.  If I were new to the market and were simply shopping on specs, I would be extremely likely to overlook the K312i and that would be a mistake.  While I think the Tangent Theta I talked about above is the best overall design here (for anything that needs no more than 12 mrad of adjustment), the Kahles has a lot to recommend itself as well.  For starters, this the easiest scope to get behind in this group.  Eye relief is exceptionally flexible, even slightly better than the Steiner M5Xi which is also very good in this regard.  While the top end magnification is the lowest here at 12x, that is sufficient for most applications.  Now, I am not a competitive shooter, so my take on it is perhaps a little different, but I usually shoot at around 12x or thereabouts since where I live the conditions often preclude easy use of higher mags.  What I do use higher magnifications for is reading the conditions and there, 18x does have an advantage over 12x.  Still, even at 12x I did not have a whole lot of problems reading the mirage with K312i compared to the rest of the scopes in this group.  I suspect that the shallow depth of field is the culprit here.  This more or less wraps up with the negatives.  The positives, in my opinion, far outweigh the negatives.  Firstly, the optical quality is very impressive.  Kahles is optimized for low light and at night it is the best scope here.  Tangent Theta and Minox are very close, but still not quite as good at night. Turrets tracked without any issues.  I checked and checked them again both with recoil and without it.  Tracking is spot on.  In terms of feel, I think these are my second favourite turrets in this group behind the Tangent Theta.   The center mounted parallax turret makes it easily the best scope for left-handed shooters or those who practice shooting off of both sides (something I do not do enough of).  The parallax adjustment is pretty slow, so it was easy for me to dial in the exact correction I wanted.  Illumination is well designed with low light in mind.  Since it is not combined with the parallax turret, the illumination knob is a rather understated affair on the left  hand side of the turret box.  It gets fairly bright, but not quite bright enough for effective use in broad daylight.  With that center mounted parallax and excellent eyepiece design, the Kahles is probably the most overall user-friendly design here.  

It is not compact, but on a lighter side for this group.  With the magnification range being what it is, I think this scope is at its best on compact 308 rifles, especially on gas guns.  Unlike most scopes out there Kahles is available with the windage turret either on the left or on the right side of the scope.  Now, as I mentioned earlier, I do not use the windage adjustment a whole lot, but I do use the illumination.  Depending on the way I shoot the gun, it is easier to reach on the left or right side of the scope.  For example, when using the scope of a rifle equipped with a shooting sling, my left arm is, quite literally, tied up.  In that situation, I have to be able to reach all necessary controls with the right arm without shifting my shooting position a whole lot.  The only scope that gave me a shot at doing that was the K312i with its center mounted parallax and right side illumination control.  On the other hand, when using a bipod, especially with an accurate AR, I prefer to keep my shooting grip and use my left hand for all the scope manipulations.  In that case, the K312i top mounted parallax is equally use to reach.  The illumination is a little more awkward, since it is now on the opposite side of the scope, but still doable. The reticle preferences are in the eye of the beholder.  Kahles uses a version of the MSR reticle with slight modification that is unique to Kahles.  It is a popular reticle these days and for a good reason.  It offers a lot of ranging capability and a precise aiming point.  That having been said my personal preferences recently shifted toward doing elevation and wind holds with the reticle least out to a few hundred yards, so the MSR is not my favourite design.  However, as I said, it is a personal preference more than anything.   Besides, Kahles is available with the AMR reticle that is a cross between a “Christmas tree” design and a Horus.   As I wrap up with Kahles, keep in mind, that is also significantly less expensive than Tangent Theta or Minox that I am going to talk about next.

Minox ZP5 is another extremely competitive design loosely based on the original Premier Heritage 3-15×50.  The Premier was designed by Optronika in Germany which itself was, I believe, mostly founded by a group of Schmidt and Bender engineers who were not happy about management changes at S&B.  I am not going to go through all the details of what happened to Premier and Optronika, but the relevant detail is the Minox and Optronika merged a couple of years ago and became one company.  The tactical scopes introduced by Minox are the result of that merger.  Optical quality is superb.  I think Tangent Theta edges it out slightly, but it is close enough to where it might be sample variation.  The turrets use conventional reset method without al the tool-less reset complications that larger Tangent Thetas have (and Premier had), However, they clearly gave a lot of thought to ergonomics and typical usage.  As I mentioned earlier, the white paint on the turrets has incredible visibility in low light and the use of triangles for zero settings makes them very easy to see.  

The overall feel of the turrets is very good, especially considering that they offer 15 mrad per turn. However, like with virtually all turrets of this type, the clicks are a bit closer together than I like.  Still, if you want a lot of adjustment per turn, this is a nice design and after a little acclimatization, I was able to use the scope adjustments by touch.  The magnification control is also a little different than on most scopes.  In that regard, it is similar to Leupold Mark 6 and it is overall the design I like the most in this group: the magnification ring has a lot of length to it taking up a significant portion of the eyepiece.  The whole eyepiece does not rotate, like it does on the Nightforce, but it is still very easy to grab.  Eye relief flexibility is similar to that on the Tangent Theta (the optical system designs between these two are clearly related) and not quite as good as the Kahles.  It is very serviceable though.  The reticle is Minox’ MR5 and it looks somewhat similar to the MSR with an additional rangefinding feature in the lower left quadrant.  I have a suspicion that this particular feature is a solution looking for a problem, but it works and is easy to adjust to.  The line thicknesses are well weighted and I like the illumination.  It is clearly designed with low light in mind as it gets very low for night time use.

Vortex Razor HD Gen II 3-18×50 is next on my list, and frankly, ranking its position in this group has been extremely difficult.  First, I have to mention the “elephant in the room”: this scope is bloody heavy!  With that out of the way, I have to grudgingly admit that I do not have anything else to complain about. Literally nothing.  It is a superbly well rounded design.  It covers the broadest magnification range here (along with the Mark 6).  It can hang optically with everything out there. Tangent Theta and Minox are a bit better, but the difference is small.  The scope is very easy to get behind.  It also has the most full featured turrets here with both zero stop and turret lock. Resolution is good.  Contrast is good.  Turrets tracking is absolutely flawless.  Adjustment range is sufficient for just about anything you might want to do. The reticle is my favourite design in this group.  It gives 10 mrad of holdover with the Christmas tree that ends up reasonably unobtrusive when I do not need it.

The rest of the reticle is similarly well conceived with good visibility across a range of lighting conditions and well executed illumination.  The original Razor HD was a very well engineered scope, but the Gen II leaps beyond it in every way possible.  The only thing that stands in its way is weight.  For many applications, weight does not matter.  However, for those applications, why would you go with the 3-18×50 scope when there is a 4.5-27×56 Razor Gen II that is marginally bigger and marginally heavier, while offering a bit more magnification and a larger objective for more reach?

Aside from that objection, Vortex Razor HD Gen 2 scopes raise an interesting question. Since you can get one of these (or the larger 4.5-27×56) for $2300-$2500, and if you do not mind the weight, why would you be compelled to buy anything more expensive.  It is a question that the makers like S&B, Tangent Theta, Hensoldt, etc have to answer.  In a side-to-side test I did, the Tangent Theta is better (and in case of the TT315M, it is lighter, which is important for me).  However, in principle, the model that competes directly against the Gen II is the TT315P with its 34mm tube and larger turrets.  It is a full $1k more than the Vortex and if paying my own money, it is not clear to me whether the price difference is worth it.  Another example is with the Minox ZP5 which I am very impressed with.  However, it is a solid $600 more than the Razor and I prefer the reticle in the Razor.  The optical performance is sufficiently close where for my purposes, I would go with the Razor Gen 2.

Steiner T5Xi 3-15×50 is the best bang for the buck in this group.  It is significantly less expensive than all of the other scope here and it mostly hangs with them without any issues.  As I mentioned earlier, it had some early hiccups with the turrets, but those appear to be resolved.  The scope is compact for the configuration and optically pretty well sorted out.  The FOV is a bit on the narrow side for this group, but aside from that, optical compromises in it are fairly minor.  Still, I see more difference between this scope and the Tangent Theta, than I do between TT and Razor Gen II.  However, the Tangent Theta is $1200 more, so it better be better!  $1800 is still a lot of money, but honestly, I do not have all that much to nitpick on with this design.  It is reasonably easy to get behind, though not as easy as Kahles and Steiner M.  There is some flare, so it really benefits from leaving the sunshade on.  However, the flare is not excessive. Contrast is not as pronounced as on the TT and Minox, but respectable, Resolution is pretty good.  The SCR reticle, however,  leaves me cold.  It is a very busy reticle with very poor low light visibility if your battery is out.  KIt gives you a lot of feature for ranging, but not for holds.  Illumination is pretty decent, but make sure you have a spare battery.

Side focus knob, showed a little hysteresis, but nothing major. The turrets tracked well and I spent a LOT of time with them.  I like the second turn indicators (little windows in the turret) and I like the overall configuration of the turrets: they are low and wide with an easy to set zerostop.

Ultimately, if you are comfortable with the SCR reticle, this scope is well worth looking at.  For the money, you’d be hard pressed to do better.

Steiner M5Xi 3-15×50, on the other hand, was a bit of a disappointment.  Mind you, if it cost less, I would be a lot less picky.  However, it is sorta telling that I liked the somewhat less expensive T5Xi more.  There was nothing wrong with how the M5Xi functioned: turrets tracked, the scope stayed zeroed and the eyepiece is exceptionally easy to get behind.  That was the one thing where the M5Xi really did well: flexibility of eye relief.  It was the only scope in this group to compete with the Kahles in that regard. However, the turret feel was mushy and optics were not good enough for the price.  At $3k, this is one of the more expensive scopes here along with the Minox and TT, and both of those run circles around the M5Xi in terms of image quality.  I hope I received a bad sample, but this one is underwhelming. At its core, the problem was significant susceptibility to flare that was difficult for me to block even with a sunshade.  This effect was most pronounced at higher magnifications.  The scope I had came with the MSR reticle.  Steiner’s version of it has a slightly bolder center aiming crosshair, which I sorta liked.  I generally like reticles on the bolder side.  As I have mentioned elsewhere, I prefer reticles with wind holds at distance, but that is a personal preference.  Steiner’s MSR is well executed and I did not have any issues with it.  

Reticle illumination on this Steiner is excellent.  It is very well calibrated with no bleed and quite bright when I need it.  I spent some time beating it up and it is largely a competent design that is brought down a bit by the flare and mushy turrets.  Its most direct competitor here is the Minox ZP5 and I prefer the Minox overall. Then again, as I mentioned above, The Vortex Razor Gen II creates a bit of a value problem for both Minox and Steiner.

Now, we get to the two smaller scopes in this group.

Nightforce ATACR F1 4-16×42 really peaked my interest because the earlier NXS F1 was a very competent design with somewhat disappointing optics.  When Nightforce came out with the ATACR, the optics looked much improved, but it was a SFP design which is not my cup of tea in this range applications.  I was all set to look at the larger 5-25×56 ATACR F1, then I saw the 4-16×42.  I think that this is a great configuration for compact precision rifles, so I rounded it up to compare to the Leupold Mark 6 (that is really how this whole article idea started).  The TACR F1 is a fairly compact scope, although the Leupold Mark 6 is still smaller and a fair bit lighter.

In the picture above, from left to right: Nightforce, Tangent Theta, Kahles, Leupold Mark 6, Minox M5Xi and original Steiner Military 4-16×50.  

Earlier Nightforce scopes had good resolution, but were a little dull on the contrast side.  The ATACR F1 suffers from none of that. The glass quality is excellent and it did not suffer from any particularly unusual optical artefacts.  Overall optical quality was similar to the Vortex Razor Gen II, which is very good company to keep.  It is priced similarly also, so the basic question I phrased earlier pertaining to why you would want to pay an extra grand or two for a similar S&B or something along those lines applies here well.  The ATACR F1 with its Mil-R reticle is a very well rounded design and the Mil-R matches it well.  It is a comparatively simple looking reticle with a lot of ranging features, which I like.  I got used to it fairly quickly and liked it enough to drag it with me on a pig hunt.  Although the reticle does get fairly thin at low magnification, it worked perfectly well for my purposes and was quick enough to pick up.  The turret design is easily one of my favourites.  It seems similar to Leupold’s M5C2 turret and I am not sure who came up with it first.  There is a lock button, which keeps the turret locked at zero position.  The turret is low and wide, so it does not catch on stuff.  Most importantly, it tracked perfectly.  Windage turret is a simple covered design, which I like a lot.  I never touch that after sighting in.  Eye relief was reasonably flexible and even with some unorthodox shooting positions, I had no issues whatsoever.  The only real weakness of this scope is the design of the reticle illumination.  It is a pushbutton arrangement integrated into the parallax adjustment knob, similar to the original March design.  It has four illumination settings and the lowest one was a bit too bright for low light and the highest one is not bright enough for bright light (same complaint as I had with March until they introduced the low power unit).  To change magnification, you rotate the whole eyepiece, which is common to most Nightforce designs.  I am not a fan of this arrangement since it rotated the lens covers.  Nightforce uses Tenebraex covers which can rotate independently to rectify that.  However, I prefer the more conventional arrangement with a non-rotating eyepiece myself.  Overall, I liked the Nightforce

Lastly, we get to the Leupold Mark 6 3-18×44. I really wanted to like this scope and despite its shortcomings, I do.  It is the smallest and lightest scope in this group by a significant margin, which really appeals to me.  It was an excellent match for my 6.5 Grendel.  It was the only scope in this group that worked well on the Grendel in term of weight and balance.  It was not as good as the competition optically, which I sorta expected because of the size, but it was still quite good.  Good enough for me to be comfortable with the tradeoff.  What I was not comfortable with was the stinky turret.  M5B2 turret has well explored issues and as far as I am concerned, this scope is to be used in a set and forget mode: use the reticle for holdover.  Another problem is the illumination, or more specifically lack thereof.  To get this scope with illumination, you have to pay an extra thousand dollars, which I find absolutely preposterous.  The reticle in the scope I looked at was the CMR-W.  When I talked to the Leupold product manager in charge of this scope, I mentioned that they sent me a scope with CMR-W reticle.  His reaction was: “#$%&, I wish they has asked me first!” Despite that, I was mostly alright with that reticle.  There are a couple of things about it that are odd, like the mil-scale for range finding is sufficiently far to the left of the FOV, where at top magnification (where you would be ranging), it is outside of the FOV.  The reticle itself is pretty coarse which I find rather practical (I am probably alone on that) and very visible under a range of conditions.  

Besides, to work well in a FFP scope without illumination the reticle does have to be fairly thick.  One thing I really like is the horseshoe arrangement in the center with the floating dot.  At high magnification, the small dot is your primary aiming point.  At low magnification, the horseshoe looks like a large dot and becomes an aiming point.

With all of that, fundamentally, despite its flaws, the Mark 6 is a very interesting design.  The only scope I can think of that is similarly compact with a broad magnification range is March 3-24×42.  However, the Leupold is easier to get behind, which is important for the applications I have in mind.  It also has a significantly less shallow depth of field which makes it easier to use.  As is, the March is a more complete design owing to the turrets.  However, after some consideration, I think I would like to revisit the Mark 6, but configure it differently.

First of all, I want to make it clear that while the Mark 6 is not as good optically as the best scopes in this line-up, it is still very good and there are very few shots that I can take with Tangent Theta and can not take with the Mark 6.  On top of that, I like the compactness of it.  With that in mind, I think I will experiment with a different version of the Mark 6, the one with David Tubbs’ DTR reticle.  I ran into Favid a few years ago at SHOT Show and we have been discussing his DTR reticle every once in a while.  I think it is a great idea and offers an excellent nearly self-contained system.  He has his reticle in the illuminated Mark 6:

While not cheap, I think this offers an incredible capability in a compact package, and I fully intend to get my hands on one and properly work it out.  

After all that wordiness, I figured I should make a short summary of the recommendations that I can come up with based on spending a pretty significant amount of time with these scopes.

If you’ve got $3k to spend and 12mrad of available turret movement is enough, get a Tangent Theta.  It is the best allround scope in this group and it is light enough to double as a hunting scope if need be.  It was equally at home on my Desert Tech SRS 6.5x47L and on a LR-308 clone.  I even tried it on my Tikka M695 hunting rifle and it worked well there too (that was kinda fun when I ended up next to some yuppy with a fancy custom rifle at the range; he was not happy about a bone stock hunting rifle outshooting his pride and joy.  When he looked through the Tangent Theta, his jaw dropped).

If your budget stops around $2400 and weight is not a major concern, you can’t go wrong with the Vortex Razor HD Gen II 3-18×50.  It is an extremely complete package.

For a large frame gas gun, or if you shoot lefty with any regularity, Kahles K312i is definitely worth a look.  That center mounted parallax makes it uniquely ambidextrous.

If you really want a high end scope, but a mere thought of spending upwards of $2k on one gives you an ulcer, you should give Steiner T5Xi a chance.  I liked this scope a lot and while the reticle is not ideal for my purposes, that is a personal preference.

Lastly, if you want the most compact package while still having high magnification available for you, see if you can work within the limitations of the Mark 6 3-18×44.  For a precision small frame semi-auto, it may be worth the trouble.

 Posted by at 10:37 pm

  14 Responses to “High End Tactical, Part V: The Cruiserweights”

  1. Hi Ilya, very very good data I love all the info on your blog. I have a question. The FOV you listed is at 1000 yards, is that correct? If it is, how do I convert it to 100 yards number at the same 10x magnification?

    I am compiling data for my next purchase and FOV is one of my top criteria then optical quality and tracking. I would love to see how the new Razor HD AMG will compare to these scopes since they solved the weight issue. Particularly i’d like to see how it will compare with the TT315M and the Kahles 624i.

  2. Nice article. I’ve been waffling on how to scope my 20″ SR-25 for a while and while I love the Kahles 6-24 and the SKMR reticle that is just too big for the gun IMO. Looking at other options always seemed to come to some sort of deal killer as well. The 3-18 Leupold I just can’t see springing 3200 bucks for and I’m not huge on the reticles. Your favorable review of the K312i got me thinking about it (I can find NO reviews of it anywhere else) and this weekend Europtic had them for 602 bucks off on sale so I sprung for one. I went with the AMR reticle, hopefully it is easily visible at 12x.

    • Thank You.
      Let me know how that scope works out for you. I have not tested the SKMR reticle in it, so I can’t really say much about it. There was no issue with reticle visibility in the scope I tested, though, so I am sure SKMR will work fine as well.

      • To be honest I would have preferred about 15x on the top end but I just couldn’t pass up the chance for a k312i at 1800 and change. Mirage usually requires dialing down a bit where I live in the summer and I never felt held back by a USO 1.8-10×44 ERGO I had on a .308 AR a few years ago so I took the plunge.

        Thanks again for this review. While info on the k624i is abundant that is not the case for the k312i.

        • Well mine was a dud. Gains extra mils over 8 in elevation to the tune of half of a mil by 14 mils dialed.

          Reticle also shifts vertically when parallax is adjusted.

          • That sucks. Did you tell Kahles?

          • No, the vendor I bought it from tried to push me off on to them but I want a refund. They say no so now I’m doing a chargeback and getting ugly as possible since they sold me a defective product and won’t do anything about it but say “sorry, not my problem”. If it sucks this much out of the box with zero use I will never trust it.

            Here’s a video:


          • All is well that ends well. I ended up getting a full refund and put the money towards a scope no in this review but is similar size wise—S&B Ultra Short 3-20×50. From what I’ve read this version doesn’t have the eyebox issue the 5-20 had so I’m looking forward to it.

  3. Hey Ilya how would you compare the Nightforce and Leupold? I actually bought a Leupold with the C2 turrets and the illuminated Tremor 2 reticle, but I’m not all that impressed with the glass. Funny enough I need the scope for my SRS and my Scar 17 and I shoot at Angeles as well. If you’d like to take a look at my Leupold with the new turrets you’re more than welcome.

    • I assume you are asking about Mark 6 3-18×44 vs ATACR F1 4-16×42. Leupold is smaller and lighter. Nightforce is a bit better optically and mechanically. I really wanted to like Leupold and I like how compact it is, but for that amount of money, I really want higher performance. Having come back from SHOT, there are a few scopes coming with similar configurations that are about as compact as the Leupold, but they are heavier. You need to decide how important that compactness is to you.

      • I actually was able to get my Leupold for only $2k so I didn’t pay full price by any stretch. Only reason I like those 2 scopes is because they will both be good fits for my SRS Covert and Scar. I really really like the gen 2 razor but it’s much too heavy, especially for the scar I think. Thinking about an AMG even though it’s very long.

        • Illuminated Mark 6 for $2K is a scorching deal. I am not a huge Tremor fan, but I have been thinking of picking one up with Tubb’s DTR.
          As far as the AMG goes, I plan to test one some time over the next few months.

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