Sightron SIII FT Scope 10 – 50 x 60 Test Review
Supplied by Sightron USA
Fantastic optical quality
Image snaps sharply into focus
No distance markings
Long and heavy
Not much else
VALUE FOR MONEY
Sightron SIII FT 10 – 50 x 60 riflescopes are available in a number of configurations, with choices of reticles and turrets. The subject of this comprehensive test review is the Model 25011. This Sightron SIII FT scope is fitted with click-adjustable “tactical” turrets and a Mil-hash reticle.
Obviously this is a high magnification scope. Yes, it can be used at 16x magnification (the mag limit for Field Target competition). However it has huge potential for precision long range shooting, such as benchrest competition and hunting.
At a Street Price of $1,250 – plus rings – this is clearly not just a riflescope, but an optical instrument that is intended to help you place pellets – or slugs – precisely on target. It’s also not the scope for a beginner, there’s waaaaay too much magnification for that!
So this is a scope for an experienced, expert long range shooter to match a high-quality, accurate air rifle and consistent ammunition. As such, the Sightron SIII FT scope is definitely in the upper end of the airgun scope market. For the long-range shooting perfectionist, it’s outstanding value.
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|Maximum Magnification||50 X|
|Minimum Magnification||10 X|
|Zoom Ratio||5 times|
|Objective Diameter||60 mm|
|Reticle Focal Plane||Second|
|Field Of View||9.6 Ft to 2.2 Ft at 100 Yards|
2.4 Ft to 0.55 Ft at 25 Yards
|Exit Pupil Diameter||1.2 mm|
|Eye Relief||3.8 Inches at 10 x|
4.5 inches at 50 x
There’s a choice of Sightron SIII FT 10 – 50 x 60 riflescope versions with differing etched-glass reticles.
As we can see from the illustration below, there’s a range of MOA options available, together with the Mil-hash version that’s the specific focus of this test review. Just the central red dot is illuminated on request in the Mil-hash reticle.
Sightron SIII FT riflescopes employ the company’s Zact-7 Revocoat technology. This provides full multi-coating of the optics and undoubtedly contributes to the excellent optical performance the HAM testers experienced.
|Parallax Correction||Side knob. Accessory wheel included.|
|Reticle Graduation||11 points for both windage and elevation|
|Reticle Type||Mil hash, etched glass|
|Magnification For Correct Reticle Graduation||24 X|
(Can also be used at 12 X and 48 X with correction)
|Maximum Ring Spacing||6.25 Inches|
|Tube Diameter||30 mm|
|Overall Length||16.9 Inches|
|Weight Without Accessories||30.8 Oz|
|Elevation Turret Clicks||0.18 Inch at 100 Yards,|
0.0045 Inch at 25 Yards.
|Windage Turret Clicks||0.18 Inch at 100 Yards,|
0.0045 Inch at 25 Yards.
|Closest Focus||10 Yards|
|Airgun Rated||No. PCPs only, not for use on springers or gas ram rifles.|
Sightron SIII FT 10 – 50 x 60 riflescopes have a solid, one-piece main tube which is Nitrogen-filled. The manufacturer says that it’s 100% waterproof for freedom from fogging and water incursion.
The elevation and windage turrets are of the “zero settable” type. Zero is set by loosening the #20 Torx screw in the end of the turret, rotating the knob to zero and re-tightening.
Interestingly, these (and other) Sightron scopes do NOT carry distance markings on their parallax correction/focus knobs. This is very unusual – every other scope manufacturer the HAM Team can think of carries distance markings on the parallax correction knob (or front bell) of their riflescopes.
This certainly prevents inaccurate ranges from being indicated by the scope’s distance markers, although this is typically not an issue with high-quality brands like Sightron.
Likewise, the large – 5 inch diameter – focusing sidewheel that’s included with Sightron SIII FT scopes is also devoid of distance markings. This is more understandable, as any Field Target specialist shooter will want to create and attach his/her own “range tapes” specific to one specific scope/air rifle/pellet combination.
Calibrated with distance markings, or not, SIII FT scopes focus down to a minimum of 10 Yards.
The reticle’s center dot LED is controlled by an 11-position rheostat offset at the top left of the eyepiece section.
Note that – perhaps surprisingly – Sightron does not have its own range of scope mounts. For HAM testing, we used Leapers UTG Pro rings. These have a very similar finish to that of the scope and the combination worked well together in practical use.
The optical performance of the Sightron SIII FT scope tested by HAM was nothing less than superb!
The image was very sharp, with high contrast across the field of view. There was no visible evidence of barrel or pincushion distortion (the effect where straight lines become bowed at the edge of the image).
Nor was there any sign of color fringing. Even at the edge of the image, black lines were sharply-edged black and white areas looked bright white. There was no tendency for black lines to look blue and and fuzzy, or white areas taking a color cast.
Of course, most users spend the majority of their time concentrating at the center of the image. There, the image was super-clear and contrasty.
To gain an appreciation for the level of optical performance delivered by the Sightron SIII FT 10 – 50 x 60 scope on test, we used an industry-standard USAAF 1951 test target. This was set-up at exactly 10 Yards from the turrets of the scope and in the center of the field.
The USAAF test target has blocks of lines at different spacings. The smaller the block of lines that can be seen, the sharper the scope.
Here’s how the SIII FT scope performed…
Given that the overall width of the test target is just 1 7/8 Inches, these blocks of lines are very tiny indeed. As you can see, they become so tightly packed that they become inseparable when reproduced in this illustration.
At 10X magnification with the Sightron SIII FT scope tested by HAM, the smallest block where I was able to differentiate individual lines is indicated in the image above. Each of those lines has a width of 500 micrometers, that’s just 19.6 thou.
So, we can clearly see features less than 20 thousandths of an inch wide at 10 yards and 10 X magnification with this scope. That’s extremely impressive!
At 50 X magnification, I was able to differentiate individual lines in the much smaller block shown. Here, each line is just 140 micrometers wide. That’s 5.5 thou! Yes, we can clearly see individual features just 5.5 thou wide at 10 yards with 50 X magnification. With better eyesight than mine, you could possibly do even better. Wow!
MECHANICAL PERFORMANCE – 1
Mechanical performance of the Sightron SIII FT scope tested by HAM was also outstanding!
Let’s start with eyepiece correction, as this is likely to be the first adjustment any user will make to a riflescope…
All Sightron scopes are preset with 0 diopter eyesight correction for 20/20 vision. If you need to make an adjustment, however, the the eyebell adjustment is quite easy to rotate, yet stays in place securely. There’s no eyebell locking mechanism, but one is clearly not required.
In HAM testing, the reticle snapped into and out of focus crisply when rotating the eyebell. This means it’s easy to be sure the correction has been set correctly for any person’s individual eyesight requirements.
The next mechanical operation most users will make is to adjust focus. We’ve already commented on Sightron’s lack of ranging marks on the side focus knob.
It has to be said that the small diameter side focusing knob is rather stiff to turn. However, it is intended to be used with the large – 5 Inch diameter – sidewheel. When this sidewheel is used, it’s a delight to change focus! The wheel rotates with just the right amount of effort from the user, yet does not move from the chosen position.
Another important feature is that there was zero detectable focus backlash. This means it was not necessary to go past the point of sharpest focus and then rotate the knob back slightly to set it at the correct, sharpest position. This can be the case with some riflescopes, but not with the Sightron SIII FT scope tested by HAM.
Operating the zoom ring also required quite a large amount of effort. Once set, the magnification you select is never going to change unintentionally: you can be sure of that!
It’s true that many shooters set their zoom riflescopes to one magnification – particularly if using holdover for elevation and windage correction, as most airgunners do. However, some other Sightron scopes are fitted with a fold out lever to make zooming easier. HAM feels that such a lever could be incorporated into the SIII FT scopes, even though it may not often be used.
MECHANICAL PERFORMANCE – 2
Being a Second Focal Plane design, the Sightron SIII FT scope’s Mil hash reticle is designed to be used at one specific magnification. In this case it’s 24 X and the zoom ring is marked appropriately. It can also be used for holdover at 12 X and 48X by doubling or halving the 24 times values.
This gives flexibility for using holdover in – say – Field Target shooting where 12 X was common, or for long range benchrest competition where 48 X would be an advantageous magnification. Of course, the current FT maximum magnification of 16 X can be calculated, too, as a factor of 1.5 times the 24 X value.
The tactical turrets fitted to this scope are models of clear marking and easy use! Click adjustments for both elevation and windage turrets are superbly implemented. Rotating these turrets requires just the right amount of effort, yet the clicks have a distinct, precision feel. This is the result of Sightron’s ExacTrack Windage and Elevation System.
Each click of elevation or windage makes a change of 0.05 MRAD. That’s a difference of 0.18 Inches in Point Of Impact at 100 Yards, or 0.72 Inches at 25 Yards.
The HAM testers never “overshot” the required number of clicks by accident, as it’s easy to do with some cheaper scopes when making turret adjustments. Yet the turrets also hold their position in a way that means they are very unlikely to be rotated by accident.
The zero set turret adjustment worked effectively and easily, too. Just as it should do!
COMPARISON TO MAKERS CLAIMS
The Sightron SIII FT 10 – 50 x 60 riflescope tested by HAM certainly met-up to its manufacturer’s claims!
Close focusing capability is an important capability for most riflescopes fitted to airguns. The SIII FT has a manufacturer’s specification of 10 Yards for closest focus.
In practice, we found that the closest focusing distance was exactly 10 Yards from the turret of the scope. AT 50X MAGNIFICATION!!!
This is extremely impressive! Typically scopes will focus closer at their minimum magnification than the highest. But the SIII FT managed to match the company’s close-focusing claims even at the highest magnification.
Field of View was also exactly matched in HAM testing. Sightron specs give a FOV of 9.6 Ft at 100 Yards using 10 x magnification. That translates down to 11.5 Inches at 10 Yards – exactly what we measured.
At 50 X magnification, the FOV claim is 2.2 Ft at 100 Yards. That equals 2.6 Inches at 10 Yards. Again exactly as measured.
EASE OF USE
There’s no doubt that Sightron SIII FT scopes are relatively large, heavy units. This, together with the very high maximum magnification capability, means that they are a self-selecting choice for the experienced, knowledgeable airgun enthusiast.
In particular, the higher magnifications transmit every slight shake or tremor the shooter makes into a wild wobbling effect – unless the gun is supported for shooting. Shooting sticks are mandatory support at high magnifications and a good, solid shooting bench even better!
It’s important to note that Sightron SIII FT scopes have very fine reticles. This can be ideal for long range target shooting, although the HAM testers found that the reticle tends to become lost against a broken background – such as trees – particularly in low light conditions.
However, this is where the red LED illumination really proves its worth. This can be easily set to just the right brightness and the red center dot proved very popular with HAM Tester Doug Rogers when he was using it to compete in the 2020 Extreme Benchrest Lockdown Edition in November 2020.
The superb rubber eyecup also confers much benefit as it excludes stray light from around the ocular (eyepiece) lens under bright conditions. At least, it does if the shooter does not happen to wear glasses!
The front and rear lens caps supplied with the scope work, but seem rather low-rent for a scope of this quality. There’s a clear impression that Sightron put a lot of cost into this scope in the places they think important, but that doesn’t include these lens caps…
BUYING AND OWNING
As befits a specialist product, you’ll not find the Sightron SIII FT scope at every big box sporting goods store. However it is available through Sightron USA’s dealers such as Airguns of Arizona.
Each scope is supplied complete with a machined Aluminum sidewheel and a substantial 3-Inch long rubber eye cup. There’s also other expected accessories, including flip-up lens covers, cleaning cloth, spare battery and instruction manual in English only.
In fact, Sightron provides a printed spreadsheet showing Mil values at 50 Meters for every whole magnification ratio throughout the zoom range – eg 10 Yards, 11 Yards, 12 yards, etc. This data could be of considerable value to benchrest shooters when dialing-in the scope for use at fixed ranges.
Center dot LED illumination is provided courtesy of one standard CR2032 battery. This is specified for a life of 400 hours use and so should not need replacing with any frequency!
Sightron offers a limited lifetime warranty on its range of riflescopes sold in the USA. In the unlikely event that a Sightron SIII FT scope should fail due to workmanship or materials, the customer simply returns the scope to the company’s Youngsville, NC headquarters. It will be repaired or replaced at Sightron’s option. There’s similar warranty coverage available for customers outside the USA through Sightron’s international dealer network.
This excellent warranty coverage is widely supported by anecdotal evidence from Sightron customers across the web. However it does not – of course – cover damage or failures resulting from accidents, misuse etc. as you would expect.
Packaging is also a strong suit. Sightron SIII FT scopes are securely packed in double-walled card boxes with foam inserts. It’s not flashy packaging but – like the scopes themselves – it’s practical, efficient and will do its job well in ensuring that your new riflescope fights off the tender mercies of the company delivering it to your home!
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