Nikko Stirling’s Octa 2-16×50 scope

John Rutkay

Two centuries of development have made the modern scope an essential component of all but a few specialised areas of rifle shooting and one significant development trend in recent years has been the extension of the magnification range for variable scopes. In the mid-1900s, 3x magnification variable scopes such as the popular 3-9x allowed a wider field of view for closer encounters and a higher magnified sight picture for longer ranges. By the turn of the century we had 4x magnification and now scopes with 10x are available.

Significantly increased versatility is the net gain for shooters. Versatility to the point where a scope can be effective at close and medium range hunting as well as at longer range precision and target shooting is a significant step forward. A magnification range of 8x and above with well-chosen power limits can propel a scope into a new multipurpose category.

Although a multipurpose rifle and scope combination will never quite match one specialised to a particular task, it can be relied on to do at least a satisfactory job in any situation. Practicalities limit a hunter to one rifle and scope at a time, so by choosing a multipurpose combination a hunter is simply stacking the odds on being well equipped for any eventuality.

At the range our hunter can wind up the power and enjoy a magnified sight picture with reduced aiming error to test and develop ammunition, sight-in or participate in target competition for valuable practice and familiarity with the rifle. While these are good reasons for buying a wide magnification range scope, their price has been somewhat of a deterrent for the average shooter as most of these scopes come from high-end manufacturers with premium glass, coatings and build quality. They’re about three times the price of an average hunting rifle.

Australian manufacturer Nikko Stirling has been a part of the variable power scope industry since the 1950s, making affordable, solid-performing durable items. It recently released the 10x  power range C-More and 8x range Octa variable series so currently makes options with three, four, five, six, eight and 10x magnification. To see their impressive range download the Catalogue 2019 at

Their 8x range Octa 2-16x50mm scope was chosen for this review as it’s in an affordable price range, roughly the cost of a lower-valued hunting rifle. Added to this was the belief that multipurpose scopes are the way forward for any keen shooter looking to make the most of the diverse hunting and shooting opportunities available in this country. The scope was supplied to Australian Shooter courtesy of Outdoor Sporting Agencies.

The Octa looks classy with black anodised scratch-resistant finish and modern design. The stout 30mm tube appears proportional to the substantial bell of the 50mm objective lens assembly and ample size of the ocular housing, its 35cm overall length and weight typical of a 16x magnification scope while mounting length of 155mm (6^) allows generous eye relief adjustment.

A large reinforcing boss to strengthen the tube at the turret attachments and visible step-up in tube diameter (wall thickness) at the structurally compromised power ring section are reassuring indicators of build strength and quality and naturally the Octa is rated shockproof for all centrefire calibres. Following assembly, the sealed scope is purged with nitrogen to displace air and moisture and ensure fog-free operation.

The Octa 2-16×50 has hunter-friendly capped turrets to keep the set zero secure, the thimbles held on the turret splines by a central screw which can be removed to reset zero after sighting-in with thimbles finger adjustable and clicks easily felt, controlled and counted. Adjustment increments are the familiar ¼ MOA per click and clearly marked. An elevation and windage adjustment range of 80 MOA ensures a reliable 40 MOA in each direction from original zero.

Parallax adjustment is on the left-side turret, the most convenient position for use in the field, the parallax free distances marked being surprisingly accurate and therefore useful. This turret also controls reticle illumination and houses the battery. Only the central dot of the reticle is illuminated on the Octa, the preference of most hunters as any more lighting of the reticle is a distraction.

There are red and green colour options with variable control between low and daylight visibility and a distinctly-felt audible ‘off’ position. The power ring is clearly marked, easily gripped and its resistance to rotation strikes a good balance between ease of use and staying put. A neoprene padded ocular fast-focus ring will sharpen the second focal plane reticle image for less than perfect vision and protect eyebrows if needed.

The etched glass reticle allows the cross-hairs intersection to be replaced by a hunting dot which is normally black but can be precisely illuminated to make accurate shot placement possible in limited light. This is a highly desirable feature on the Octa as it goes a long way towards bridging the low-light effectiveness gap between a highly expensive and this affordably priced scope.

Optically, well-established brands of scopes are all ‘good to very good’ in bright daylight. A multipurpose scope needs to also perform well in the foggy dawn, evening dusk and under spotlighting conditions and the Octa was tried in such conditions and impressed. The morning fog didn’t cooperate but the bushfire haze was a fair substitute which affected the spotlight as well.

It was also directly compared to a more expensive US brand with 56mm objective lens in lowlight conditions. Both scopes were set to 8x magnification and aimed into the same lowlight areas but I couldn’t see a difference in resolution, the Octa’s fully multicoated lenses obviously doing their job on light transmission.

In use, the Octa looked at home and balanced well on the rifle with markings clear and controls easy to operate. Zeroing the scope at 200 yards was a simple task as click adjustments were followed reliably by the point of impact, groups shot as tight as ever, indicating a rock solid zero. A quick test for target shooting suitability saw two shots fired at the 200-yard Field Rifle target from the sitting post position. Both landed comfortably in the 10 ring but the 6mm bullet holes could not be reliably ‘spotted’ on 16x power in difficult light (any shooter looking to use their regular hunting rifle for Centrefire Field Rifle competition and avoid the need for a spotting scope could consider the 3-24×56 Octa).

The Nikko Stirling Octa 2-16×50 performed well in all areas tested and showed no fault or weakness. There’s a lifetime warranty on defective scopes to the original owner following product registration, excluding scopes exposed to abuse or unauthorised work.

This is an effective blend of all the ‘must-have’ features of a good multipurpose scope, namely low and high magnification, easy parallax adjustment, good lowlight performance and an illuminated reticle as well as the assumed fundamentals of reliable zero, optical clarity and sturdy airtight construction.

The wide field of view on 2x magnification bolstered by the quick target acquisition of the uncluttered 4-Dot reticle makes the Octa ideal for hunting in heavy cover. For small or distant game and paper targets, the 16x magnification combines well with the precisely etched glass reticle. Good lowlight performance of the fully multicoated lenses (further enhanced by the precise aiming made possible by the illuminated reticle), complete the comprehensive abilities of this outstanding product. For the user it means an effective response to more shooting opportunities, extended hunting time in the productive lowlight periods as well as being a pleasure to use on the range.

It’s easy to recommend this scope as it has no apparent fault or weakness yet is a distinct notch above the typical variable scope in terms of effectiveness in a wider range of situations. An astute hunter will see this as well as the outstanding value for money, considering scopes with similar quality and features can cost about twice the price of the Octa. Closer to home I’m keen to see a Nikko Stirling Octa become a permanent fitting on the Model 700 used in this review.


Manufacturer: Nikko Stirling

Origin: Made in China

Model: NSOC21650

Power: 2-16x (8x zoom)

Length: 352mm

Field of view at 100m: 2.6-21.1m

Main tube: 30mm (one piece)

Objective lens: 50mm

Lenses: Fully multicoated

Reticle: Glass, 4-Dot, illuminated

Parallax focus: Side turret (range 9m-infinity)

Eye relief: 90mm (2-16x)

Turrets: Capped, ¼ MOA/click

Sealing: Dust, fog and waterproof

Recommended retail price: About $550 but shop around

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