What does the new GPO Spectra 6x 3-18x56i G4i Fiber riflescope offer more than other hunting optics in this price range?

The left turret of the GPO Spectra 6x 3-18x56i houses the red dot control and battery compartment as well as the parallax compensation.

The German optics specialist German Precision Optics, or GPO for short, is expanding its Spectra line of riflescopes with a 6x zoom factor. Our colleagues were able to see for themselves that GPO's quality and price are a good match when they tested the GPO 6x 4.5-26x50i, which can be used both for sport shooting and long-range hunting. You can read their test report here on all4hunters.com. But now we are talking about a riflescope that was primarily designed for hunting. This is because the Spectra 6x 3-18x56i, previously only available with the BRi ballistic reticle, is now being joined by the Spectra 6x 3-18x56i G4i Fiber, a riflescope for hunters. GPO is addressing the G4i Fiber version to the hunter who is looking for a scope with a classic German crosshair reticle in the 2nd focal plane with a very fine central illuminated dot at the crosshairs intersection in the center. In this case, very fine means that the illuminated dot introduced into the target image using fiber optics obscures less than 1 cm of the target at a distance of 100 m.

The G4i Fiber reticle uses modern fiber optic technology, which enables a very fine illuminated dot.

We have now also introduced all the components that give this reticle its name: "G4" for German 4, meaning that it is based on the German 4 reticle, "i" for the fact that it can be illuminated, and "fiber" for the fiberglass that brings the red illuminated dot to the centre of the reticle. The illumination setting can be infinitely adjusted here. The control for this, together with the battery compartment for a standard 3V CR2032 Li button cell, is located in the left-hand turret, where the parallax compensation is also located. According to the manufacturer, the latter starts at 10 m and extends to infinity, whereby the sharp close-up range of our test riflescope started at around 5 m. Back to the illumination for a moment: this includes an intelligent automatic switch-off function called GPO iControl, which ensures that the illuminated dot is automatically deactivated after 3 hours of inactivity in order to save the battery. Speaking of the battery: here too, the technology informs you by flashing three times after switching on the light dot if the battery has less than 15% remaining capacity and should be replaced soon.

View from the right-hand side of the GPO Spectra 6x 3-18x56i of the adjustment turrets, from which the protective caps have been removed. The cover plates shown here can be unscrewed without tools to zero the turrets.

The 3-18x56i G4i Fiber has a 30-mm main tube, an overall length of 360 mm and weighs just under 830 g. The nitrogen-filled housing is made of matt black anodised aluminum. The adjustment turrets for elevation and windage adjustment each have a maximum adjustment range of 250 cm at 100 m, which is enough for any hunting application. The solid mechanics in the turrets are protected by sturdy aluminium cover caps. The adjustment mechanism, which can be clearly felt and heard, works with 1 cm per click at 100 m in CW mode. CW stands for Clockwise, and in this case means that the direction of rotation for moving the reticle up and to the right is clockwise. If you hold the lower end of the turrets and turn the head end anti-clockwise, you can unscrew the top plates of the turrets and lift off the actual adjustment rings for zeroing and put them back on again. This means that no tools are required to align the zero marks on the turrets with the dot mark on the tube after firing. The turrets, like the ring for adjusting eyepiece magnification, have a knurled grip. If you are out hunting with gloves or need to change magnification frequently and quickly, you will be pleased with the included throw lever. If required, this lever can be attached to the approximately 3 mm high fin on the zoom ring of the GPO Spectra 6x 3-18x56i using a screw clamp. The diopter adjustment and focussing is carried out using the classic ring on the eyepiece. This also has the aforementioned knurling and is sealed at the rear by a rubber coating to protect the shooter. The manufacturer uses lenses made of optical HD glass for this riflescope which, in combination with the GPObright multi-coating, enable a light transmission of 90%. This, combined with the fast 56-mm objective lens of the GPO Spectra 6x 3-18x56i, ensures that the riflescope, which is listed at 999 euros (RRP) and is already available in stores, offers an optical quality that is far from commonplace in this price range.

Test impressions of the new scope from the GPO Spectra 6x series: what do you get for just under €1,000?

In the test, the GPO Spectra 6x 3-18x56i G4i Fiber impressed us with its very true-colour and extremely sharp and high-contrast image right up to the edges. If the eye relief is set correctly, experienced shooters will have no problems finding the much-discussed eyebox.

The back of the target on which the box test with the GPO Spectra 6x 3-18x56i G4i Fiber was performed: the square obtained speaks for the repeat accuracy of the click adjustment.

There was nothing to criticise about the mechanics either. The click adjustment works cleanly and – as the obligatory box test after firing confirmed – with repeatable accuracy. (The box test sequence: shot, 10 clicks to the right, shot, 10 clicks down, shot, 10 clicks to the left, shot, 10 clicks up, shot). Even wet and cold did not affect the controls. The zoom ring as well as the focus ring and the one for the parallax setting are designed in such a way that they are not too difficult to move, but can't be adjusted unintentionally because they could be too easy to move. This did not change even after the scope had spent a night in the freezer at minus 20°C and we immediately moved the rings on the ice-cold optic to check them. The lighting system also coped with this part of the test without any problems. Incidentally, the really very fine illuminated dot could always be adjusted in all weather conditions, in bright sunlight as well as in cloudy rainy weather, at dusk and in the dark, so that it did not over-illuminate. Last but not least, the GPO Spectra 6x 3-18x56i showed no signs of fogging from the inside even after the cold weather ordeal. Once the objective and eyepiece lenses had been cleaned of the light hoarfrost with an optics cloth, the optic was immediately ready for use again.

The GPO Spectra 6x 3-18x56i G4i Fiber has a rugged aluminium housing with a 30-mm thick main tube, is 360 mm long and weighs just under 830 g.

GPO Spectra 6x 3-18x56i G4i Fiber specs and price


GPO Spectra 6x 3-18x56i G4i Fiber


3x - 18x

Objective Lens Diameter:

56 mm

Exit Pupil:

9.5 - 3.7 mm

Eye Relief:

95 mm

Field of View at 100 m:
11.1 to 1.9 m
Main Tube Diameter:
30 mm

Elevation Adjustment Range (at 100 m):

250 cm

Windage Adjustment Range (at 100 m):

250 cm

Adjustment per Click (at 100 m):
1 cm

Parallax Compensation:

10 m – ∞

Light Transmission (ISO 14490-5:2005):


G4i fiber in the 2nd focal plane
Reticle Illumination:Yes, stepless with automatic switch-off
Battery Type:CR2032 Li button cell

Objective Lens Mechanical Outer Diameter:

63.5 mm

Lens Filter Thread:


Eyepiece Mechanical Outer Diameter:

44.5 mm

Overall Length:
360 mm


830 g

Price (RRP):

999 euro

The all4hunters.com test conclusion on the new versatile hunting GPO Spectra 6x 3-18x56i G4i Fiber riflescope:

All in all, it is a versatile and very rugged riflescope that can show off its strengths particularly when hunting sitting game during the day and well into the twilight hours. At just under €1,000, it belongs in the mid-range price bracket, but in terms of build quality and optical performance it offers significantly better value for money than many other riflescopes in this segment. So if you are no longer satisfied with your current riflescope for buck hunting and are looking for a fairly priced alternative, you should definitely take a closer look at this riflescope from GPO in specialised shops.

You can find more information about the riflescopes from German Precision Optics on the GPO website.

You can find out more about the GPO Spectra 6x 3-18x56i G4i Fiber riflescope tested here on the GPO sales partner AKAH website. From there, you can also have the riflescope sent to a specialist dealer of your choice to inspect it and purchase it on site.

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