DiscoveryOpt ED-ELR GEN III 5-40×56SFIR FFP – In-Depth Overview

The DiscoveryOpt ED-ELR GEN III 5-40×56SFIR FFP is the most advanced member of the ELR series to date. Building on two generations of refinement, the GEN III brings increased adjustment travel, improved mechanics and carefully developed optics to a platform that has already earned a reputation in the international precision shooting community. It is aimed primarily at PRS and ELR competitors and long-range hunters – anyone who expects professional-level performance from their riflescope.

ED Glass and Optical Performance

The lenses are made from ED (Extra-low Dispersion) glass, which significantly reduces chromatic aberration – the coloured fringing that appears at image edges under high magnification and degrades sharpness. The full multi-coated SFIR (Special Film Infrared Reflection) coating maximises light transmission, delivering clear, contrasty images in low-light conditions such as dawn or dusk hunts.

• ED glass — minimised chromatic aberration, natural colour rendition
• Full multi-coated SFIR — maximum light transmission across the full magnification range
• 56 mm objective — large light-gathering surface, wide field of view (7.7 m – 0.9 m / 100 m)
• Locking diopter ring — once set for your eye, the diopter cannot accidentally shift

First Focal Plane (FFP) Illuminated Reticle

The first focal plane (FFP) reticle scales proportionally with magnification, meaning its MRAD subtensions remain accurate at every power setting – not just at a single predetermined magnification. In ELR and PRS shooting, where conditions change rapidly and the shooter often works across a range of magnifications, this is a fundamental advantage.

The reticle is optimised for ELR use: a wide windage compensation scale on the horizontal stadia and detailed elevation marks on the lower post. Red illumination is adjustable across 6 brightness levels, from a dim night setting to full daylight visibility.

• FFP reticle — accurate subtensions at every magnification
• MRAD or MOA variant — choose the system that matches your shooting practice
• Red illumination, 6 levels — adapts to all lighting conditions
• Detailed ELR reticle — wind and elevation holds in one reticle

Precision Turrets and Zero Stop

The GEN III turrets operate with 0.1 MRAD clicks (1/10 MRAD), allowing precise and finely controlled adjustments. Elevation travel is 25 MRAD (86 MOA) and windage travel is 18 MRAD (62 MOA) – both improved over the GEN II and sufficient for extreme long-range engagements. The Zero Stop mechanism allows instant return to a pre-set zero point, which is invaluable in field conditions where fast and repeatable resets are required.

• 0.1 MRAD click value — precise, fine adjustment
• 25 MRAD elevation / 18 MRAD windage — increased travel vs. GEN II
• Zero Stop — fast, reliable return to zero
• Positive, tactile clicks — easily managed even with gloves

Side Parallax Adjustment and Handling

Side parallax adjustment from 25 yds to infinity is positioned on the left side of the scope body, accessible without breaking your shooting position. This is particularly valuable in competition and when switching targets quickly. The factory-fitted throw lever on the magnification ring allows fast, confident power changes – useful with gloves or under time pressure. It can be removed if preferred.

• Side parallax — 25 yds to infinity, reachable from shooting position
• Throw lever — factory-fitted, fast magnification changes
• Eye relief — approx. 9.1 cm (5×) – 9.0 cm (40×)

Durability and Reliability

The 35 mm tube provides a robust structure and generous internal adjustment reserve. The scope is nitrogen-purged and IP67-rated waterproof – fully reliable in rain, snow and condensation. The .50 BMG recoil rating confirms it will hold zero and maintain mechanical integrity under the heaviest recoil calibres.

• 35 mm tube — robust build, large adjustment reserve
• Nitrogen-purged, IP67 waterproof — fully fogproof and waterproof
• .50 BMG recoil rating — handles the most demanding calibres
• Length: 435 mm | Weight: 1415 g

Technical Specifications

• Model — ED-ELR GEN III 5-40×56SFIR FFP
• Magnification — 5–40×
• Focal plane — FFP (First Focal Plane)
• Objective diameter — 56 mm (optical), 67 mm (housing outer diameter)
• Tube diameter — 35 mm
• Length — 435 mm
• Weight — 1415 g (scope only, without rings or sunshade)
• Field of view — 7.7 m – 0.9 m / 100 m
• Exit pupil — 9.2–1.4 mm
• Eye relief — 9.1–9.0 cm
• Click value — 0.1 MRAD / 0.25 MOA
• Elevation range — 25 MRAD / 86 MOA
• Windage range — 18 MRAD / 62 MOA
• Parallax adjustment — 25 yds – infinity (side)
• Illumination — red, 6 levels
• Zero Stop — yes
• Recoil rating — .50 BMG
• Waterproof — IP67
• Nitrogen-purged — yes
• Battery — CR2032

Box Contents

• Riflescope — 1 pc
• 35 mm Picatinny scope rings — 1 pair
• Sunshade — 1 pc
• Lens caps — 1 set
• Lens cleaning cloth — 1 pc
• Cleaning pen — 1 pc
• Levelling kit — 1 pc
• Hex wrench — 1 pc
• User manual and spec card — 1 pc
• Warranty card / QC card — 1 pc

Who Is This Scope For?

The DiscoveryOpt ED-ELR GEN III 5-40×56SFIR FFP is the right choice for anyone who needs a professional-grade precision riflescope for ELR or PRS competition, or for long-range hunting – without paying premium European prices. The 25 MRAD elevation range and 0.1 MRAD click value allow the fine adjustments required for extreme long-range work, while the ED glass and FFP reticle ensure no compromise on image quality. It performs well on .308 Winchester, 6.5 Creedmoor, .300 Win Mag, .338 Lapua Magnum and similar calibres – and its .50 BMG recoil rating means it will handle the most demanding platforms without issue.

User Feedback

The ED-ELR series has been gathering consistently positive feedback in international shooting communities. On the Rimfire Central forum, one user reported replacing an Arken EP5 5-25×56 with the ED-ELR GEN II 5-40×56 and noted that a friend sold his Bushnell Match Pro to buy a Discovery after looking through it. The same thread mentioned that Kenny at Desert Precision Gunworks had publicly praised the Discovery line as an Arken-level performer at a lower price point. (Source: Rimfire Central)

A detailed user review described the ED-ELR as standing out in glass quality and image sharpness – particularly at high magnification, where chromatic aberration starts to appear in other scopes at similar price points. The build was found to be solid and reliable throughout testing. (Source: uh.app)

If you have any questions about this scope or mounting options, feel free to contact us – we are happy to help.