Swarovski’s second generation Z6i 1-6x24 and 2.5-15x56mm HD scopes

Choosing a rifle can be a headache these days, the correct ammunition yet another and with so many new sound moderators on the market making the right choice is getting harder. Getting the right choice of scope for your stalking/vermin needs is critical too. It is not just the quality of lens, low light performance or illuminated reticules that should get your attention. But also true inner performance such as exact reticule movement, non-fogging and waterproof construction, parallax adjustments and most importantly retaining the zero once it is set.

These are all considerations for the initial first step but also the type of shooting you do greatly influences your choice on a purely physical size basis too. Large objective lenses for low light gathering are great but do you really need them and are the higher magnification specifications all they are cracked up to be. Perhaps the wide field of view and lower end magnification would fit your bill better, well I wanted to look at two scopes that fitted the bill perfectly and see what advantages they had in real life shooting scenarios.

OPTIONS

I was testing two that fitted the bill perfectly from the Swarovski’s 2nd generation Z6i range, although other similar scopes would suffice equally. One a low powered wide field of view 1-6x24mm me likes, the other a higher magnification larger objective in the form of the 2.5-15x56mm HD.

These new Swarovski`s were ideal as they are a blend of the latest technology but with the real considerations of what is important to the shooter out in the field. They both show the newer design with a slimmer more elegant profile especially in the illuminated reticule unit.

The magnification range on all the Z6i range is as it states x6 power i.e. 1-6x is self explanatory and the 15x divided by 2.5x = 6. This gives you great diversity in one scope, allowing a close range encounter in the woods to be successful yet still leave you enough magnification for a longer shot.

Also of importance are the lenses and coatings used as these define how good that image you see is in any lighting condition. The higher mag Swarovskis of x15 and above now have the coveted HD or High Definition lenses fitted. These are fluoridecoated to achieve the sharpest image possible without any of the colour fringing that can occur on cheaper makes. The smaller 1-6x24mm Z6i has Swarovski’s normal lenses coatings, multi layered and because of its lower mag and wider field of view in my tests you did not need HD lenses on these models.

COMMON FACTORS FOR OPTICS

Exit pupil: this is the objective lens size divided by the magnification to give a figure ie 6x42mm scope would be 7mm. The pupil of your eye can dilated to a maximum of 7mm therefore anything above this is wasted or below this is not optimised.

Relative Brightness (RB): This is the ability to transmit light of an object to the human eye. The RB is the square of the exit pupil ie 6x42mm gives a value of 49 (ie sq of 7mm) whereas a 12x40 scope gives a dimmer image as RB is 10.9 (ie sq of 3.3mm)

Twilight Factor (TF): Used in conjunction with RB values give a good indication of a scopes performance between objective lens size and magnification. It is the square root of the mag x objective size Therefore an 8x56mm specification has a TF of 21.2 whilst a 6x42mm has a TF of 15.9 despite both having the same RB value. So the x8 power will distinguish the target clearer at range.

Field of View: here a large objective does little unless the eyepiece is also enlarged. Narrow fields of view are fine for static targets but in a wood or running game greater vision is important. Typically a x15 power has only a field of view of 8 feet at 100 yards where as 1x power can give a whopping 125 feet or so.

Parallax: Is when a reticule seems to shift its point of aim on a target as you move your eye left to right. Most full-bore scopes are parallaxed at 100 yards but the ability to adjust this is handy on higher mag scopes.

Resolution: Is actually determined by your own vision but typically a human eye can resolve detail of a minute of arc or one – sixtieth of a degree (1/60 th).

Spherical Aberration: Is a case of light from the fringes of the lens itself focussing in front of the light that comes from the centre of the lens, thus causing a blurring of the image.

Astigmatism: This occurs when a scope cannot focus lines or straight edges sufficiently that cross each other at diverging angles. If you look and see a difference between lines running left or right and up and down or right to left then the lens has astigmatism.

Chromatic Aberration: This is when a scope cannot focus all the light rays at a single point. This is seen when the white light that consists of all the spectral colours which have differing wavelengths and therefore focal lengths do not converge and a coloured halo is seen around the image.

GOING THE WIDE ANGLE ROUTE

I like smaller, wide field of view (FOV) scopes. As they are usually smaller and therefore mount closely to the rifle and despite having a smaller objective lens like the Swarovski 1-6x24mm Z6i the low power settings still give incredibly bright vivid images for aiming.

Here we have a magnification setting of x1 to 6 that is very beneficial when stalking around the woods, be that dense undergrowth of Surrey or the dark tight knit forestry of a Scottish plantation. At x1 you have a 127.5 ft FOV @ 100 yards and an exit pupil of 9.6mm and RB value of 92.16 and Twilight Factor of 2.8. Here a close quarter encounter with a roe buck or running boar allows instantly a well aimed shot or not with the peripheral vision enhanced with that extended FOV which on a safety point of view is also beneficial!

But if you step onto a ride or reach a field’s edge there is enough magnification on tap to wind it up to x6 and still be confident to take a well aimed shot. Here the FOV is still very good at 20.4 ft @ 100 yards with an exit pupil of 4mm and RB value of 16 and a Twilight Factor of 12. I really like these smaller scopes as for 75% of all my shooting they fit the bill perfectly.

MAGNIFICENT

However there are definitely times when you need maximum, light gathering capabilities, a bit longer legs in the magnification department and razor sharp images. Here the Swarovski 2.5-15x56mm HD is a good scope. The HD glass found on the higher magnification Swarovski scopes (15x and above) give razor sharp vivid and good colour definition images. All Swarovskis have light transmission factors above the 90% level which is what you need for a sharp image and low light capability. Here the 6 power factor on the Z6 I range comes to the fore front especially when coupled with the large 56mm objective lens.

At x2.5x it’s still fine for running boar and for stalking around a dense plantation it still gives you 49.5 FOV with a RB value of 501.76 and twilight factor of 7.1 from the big 56mm lens. You can sit up a high seat all night for boar with this one or eke every last bit of light on a woodland edge. But with this model you can crank up the power to a very useable x15 which brings in those distant targets a treat. Again due to the 56mm objective you still have a good twilight factor for discerning the resolution of an image at a figure of 29 with a relative brightness of 13.9 yes the FOV has shrunk to 8.1 ft, but when you are concentrating on a distant object you have more time to consider the safe shot and check either side of the game.

FIELD USE

Theories are fine but the real test is out in the real world where wildlife have not read the rule books. Despite the horrendous weather we are having this summer or perhaps because of it, the roe in Surrey have been elusive or should I say more selective at revealing themselves.

I mounted the 1-6x24mm Z6i on my Tikka. The LD-1 illuminated reticule on this model is super speedy at locating a beast in amongst the tangle of hawthorn and dense undergrowth so common on the Surrey hills. Despite my best efforts the roe came out on top, so I changed tactics and rifle with the larger Swarovski 2.5-15x56mm HD mounted on a RPA Quadlite.

Here the HD glass was instantly appreciated and noticed as not only does it give pin sharp imagery but also there is no colour bleed or aberration and the red pelage of a Roe deer instantly pops out from the predominantly green foliage. Here the low power 2.5x allowed me to stalk the woods and rides with a good field of view and then I finally spotted two buck`s fighting, heads down and antlers entwined. The range was over 350 yards so a slow stalk cut the range to 200 . Then they disappeared into the wood the mature buck chasing hard at the youngsters heels.

I had to wait another 30 minutes debating whether I should move or stay put. This was decided for me when the younger yet still very nice buck emerged 125 yards in front of me, a quick magnification change to x12 and side parallax adjusted had me ready. Despite the rain the Swaroclean coatings did reduce the rain drops from blurring the image and utilising the good twilight factor and steady rest on the Stoney Point sticks the 120-grain Ballistic Tip bullet sped directly into the heart and he instantly dropped on the spot.