DiscoveryOpt ED-ELR 5-40×56 SFIR FFP — rifle scope engineered for extreme long-range shooting
The DiscoveryOpt ED-ELR 5-40×56 SFIR FFP was built for shooters and hunters who take long-range and extreme long-range (ELR) shooting seriously. This is not an entry-level product: it offers uncompromising optical solutions — ED glass, a first focal plane reticle, precision turrets and a Zero Stop function — features that until now were only found on scopes costing two or three times as much.
ED glass — the foundation of image quality
The use of ED (extra-low dispersion) glass is central to the scope's optical performance. This type of glass significantly reduces chromatic aberration — the phenomenon where light rays of different wavelengths fail to converge at a single point, causing colour fringing or blurring at the edges of the image. With the ED-ELR, this problem is reduced to a minimum: the image is sharp, high-contrast and true to colour, even at 40× magnification. The fully multi-coated optics provide ≥92% light transmission, ensuring a clear, bright view even in low-light conditions — at dawn or dusk.
FFP reticle — accurate readings at every magnification
The first focal plane (FFP) reticle scales proportionally with magnification. This means the MRAD subtensions on the reticle display true values at every magnification setting. There is no need to mentally calculate corrections or search for a specific magnification to take a reading: ranging and ballistic compensation are equally accurate at 5× and 40×. The illuminated centre section is red, adjustable across 6 brightness levels, and can be controlled via the side-mounted button without lifting your head from the shooting position.
1/20 MRAD turret adjustment — where the Gen I outperforms even its successor
This is the feature that truly sets the ED-ELR apart from the competition — and what makes the Gen I version particularly attractive. While most rifle scopes in this category use 1/10 MRAD (0.1 mrad) per click turrets, the ED-ELR Gen I turrets adjust in 1/20 MRAD increments, i.e. 0.05 MRAD per click. This means that at 1000 metres, a single click moves the point of impact by just 5 cm — compared to the standard 10 cm. It is worth noting that the manufacturer's newer Gen II version no longer features this level of fineness: it reverts to the conventional 1/10 MRAD adjustment. The Gen I therefore offers a superior solution in this respect from the perspective of the precision shooter. The elevation adjustment range is 24 MRAD and windage is 17 MRAD — more than sufficient to cover the ballistic demands of extreme long-range shots.
Zero Stop — reliable return to zero
The Zero Stop system allows the shooter to quickly and reliably return the turrets to the pre-set zero — without counting clicks. This is especially important in competition situations, where multiple targets are at different distances and rapid correction followed by a return to zero is essential. The mechanism is backlash-free, eliminating the risk of accidentally overshooting the zero.
Optical and mechanical construction
The 35 mm tube diameter allows for large internal adjustment ranges and provides a more robust construction than conventional 30 mm models. The total length is 423 mm and the weight is 1279 g — a reasonable figure for an ELR-class scope of this size. The side parallax adjustment (from approximately 40 yards) allows fast and convenient operation without lifting your head from the shooting position. The nitrogen-filled, hermetically sealed body provides full waterproofing, fogproofing and shockproofing. The 1500 G shock resistance rating ensures reliable performance on large-calibre firearms — including .308 Winchester, .300 Win Mag and .338 Lapua Magnum.
Who is this scope recommended for?
The DiscoveryOpt ED-ELR 5-40×56 SFIR FFP is primarily recommended for shooters competing in PRS or ELR disciplines, and for hunters who regularly engage targets beyond 500 metres and refuse to compromise on image quality or adjustment precision. It is particularly well suited to those who are specifically looking for a rifle scope with 1/20 MRAD turrets, an FFP reticle and Zero Stop functionality — and who understand that this level of turret fineness is normally a hallmark of the premium segment, available here at an accessible price. It is also worth considering for newer precision shooters who are serious about developing their long-range skills: this scope will grow with them, and will not need replacing for many years.
What users around the world are saying
In international shooting communities — including the Rimfire Central and Airgun Nation forums, as well as the Judge.me review platform — the DiscoveryOpt ED series has received consistently positive feedback. Multiple users highlight that the glass quality and turret tracking accuracy are surprisingly good for the price point. One reviewer reported that a friend, after looking through a Discovery scope for the first time, sold his Bushnell Match Pro and bought a Discovery instead. A specialist at Desert Precision Gunworks rated Discovery optics on a par with Arken in a podcast, but at a lower price. The series holds a 4.64 out of 5 star average on Judge.me, based on 70 reviews. Critical comments typically focus on the relatively large size and weight — which is a natural characteristic of any 40× ELR-class rifle scope.
Sources: Rimfire Central forum, Airgun Nation forum, Judge.me review platform
