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Magnification: 5–25xObjective Lens: 56mmTube Diameter: 34mmFocal Plane: First (FFP)Adjustment: 0.1 MIL per clickWeight: 37 ozIllumination: YesZero Stop: IncludedSuperb clarity for its priceRock-solid zero hold and trackingExcellent turrets with tactile clicksGreat for long-range and precision buildsHeavier than mid-range opticsLimited illumination brightness in daylight
Magnification: 1–8xObjective: 24mmFocal Plane: First (FFP)Reticle: EBR-8 MOATube Diameter: 30mmIllumination: YesWeight: 23.9 ozGreat for CQB to mid-rangeClear glass with vibrant illuminationSolid build and easy adjustmentVortex lifetime warrantySlight edge blur above 6xTurrets not designed for repeated dialing
Magnification: 3–18xObjective Lens: 50mmFocal Plane: First (FFP)Reticle: ACSS Athena BPR MILTube Diameter: 34mmAdjustment: 0.1 MILWeight: 33 ozACSS reticle offers fast rangingExcellent clarity and zero retentionIdeal for 200–800 yard precision workAffordable compared to competitorsSlightly heavyTurret caps feel less premium
Magnification: 3–9xObjective: 40mmTube: 1-inchFocal Plane: Second (SFP)Weight: 12.2 ozLightweight and compactCrystal-clear opticsExcellent low-light performanceBacked by Leupold’s lifetime warrantyNo illuminationNo parallax adjustment
Magnification: 1–8xObjective: 28mmTube Diameter: 34mmFocal Plane: First (FFP)Weight: 26 ozLarge 34mm tube for bright imageExcellent mechanical feelFFP reticle ideal for rangingDurable constructionSlight fisheye at 1xLimited eye box at high power
Range & Precision Work:
Go for higher magnification (e.g., Arken EP5 or Primary Arms 3-18x). You’ll benefit from detailed glass and precise turrets.Hunting:
A lightweight scope like the Leupold VX-Freedom gives excellent clarity and portability.Tactical / Competition:
LPVOs (Vortex Strike Eagle or Arken EP8) allow quick transitions and reliable BDC reticles.Focal Plane: FFP for long-range; SFP for hunting and simplicity.Tube Diameter: 30–34mm tubes offer more adjustment and light transmission.Weight: Keep it under 35 oz for balance on ARs.Durability: Look for waterproof, shockproof construction with positive turrets.
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Best Scope for 20 Inch AR – Precision and Performance in One Platform
When it comes to maximizing the accuracy of your AR platform, choosing the best scope for 20 inch AR is one of the smartest upgrades you can make. The 20-inch AR-15 or AR-10 barrel is an ideal length for balancing velocity, accuracy, and portability — but its potential is only realized when paired with quality glass.
In this guide, I’ve tested and compared some of the top optics suited for this barrel length, evaluating real-world clarity, turret tracking, durability, and overall shooting performance. Whether you’re hitting steel at 600 yards or hunting coyotes at dawn, these scopes deliver exceptional results.
🥇 Top 5 Scopes for a 20-Inch AR
Each of these optics has been mounted and tested on both AR-15 (5.56 NATO) and AR-10 (.308 Winchester) rifles with 20-inch barrels. The combination delivers incredible velocity and stability, making it the perfect platform for both close-quarters and extended-range work.
Detailed Reviews
1. Arken Optics EP5 5-25x56 FFP Rifle Scope
The Arken Optics EP5 5-25x56 FFP is an affordable powerhouse built for precision shooting. It’s a feature-rich optic that performs like a $1500 scope but comes in under $600. On my 20-inch AR-10, chambered in .308 Win, the EP5 delivered crisp resolution at long range and consistent zero retention even after 500 rounds.
Product Specs
Pros
Cons
Glass Clarity & Reticle
The Japanese ED glass offers excellent light transmission and minimal chromatic aberration. The VPR MIL reticle is precise, with clean hash marks ideal for holdovers and ranging. At 25x, I could easily spot bullet trace at 600 yards.
Eye Relief & Eye Box
At 3.4 inches, the eye relief is generous, and the eye box is forgiving between 5x and 18x. Beyond that, it tightens slightly — typical for a scope in this class.
Durability
I tested it in light rain and dust; it shrugged off moisture easily. The matte finish resists scratches, and the turrets still feel solid after heavy field use.
Elevation & Windage Knobs
The clicks are precise and audible. I performed a box test at 100 yards, and it tracked perfectly back to zero.
Magnification & Parallax
Magnification adjustment is smooth and firm. The side parallax knob focuses down to 25 yards, excellent for close zeroing.
Mounting & Accessories
I used a 34mm Arken one-piece mount with a 20 MOA cant. It fit perfectly on the AR’s Picatinny rail with enough clearance for the 56mm objective.
Personal Experience
After zeroing in just 8 rounds, I held sub-MOA groups at 200 yards. Even after a few range trips and over 400 rounds, the zero never shifted.
Verdict:
The EP5 is a beast for long-range shooters using a 20-inch AR-10 or AR-15. It rivals optics twice the price and feels built like a tank.
2. Vortex Optics Strike Eagle 1-8x24 FFP
The Vortex Strike Eagle 1-8x24 FFP is an excellent choice for AR users who want a flexible optic — one that works from point-blank out to mid-range distances. Mounted on my 20-inch 5.56 AR, it performed beautifully for rapid engagements and still gave precise shot placement at 400 yards.
Specs
Pros
Cons
Clarity & Reticle
The glass is excellent for its class, with crisp resolution in daylight. The EBR-8 reticle is etched and provides an intuitive BDC grid perfect for 5.56 ballistics.
Eye Relief & Comfort
At about 3.5 inches, it’s perfect for AR use. The generous eye box makes quick target acquisition effortless.
Durability
It’s nitrogen-purged and shockproof — I banged it around in the truck, and it held zero perfectly. The Strike Eagle easily survives hard use.
Personal Experience
On a 20-inch rifle, this optic shines for 3-Gun or patrol-style setups. It transitions fast from 1x to 8x, and the illuminated reticle helps in dusk shooting.
Verdict:
The Strike Eagle FFP is an outstanding LPVO for a 20-inch AR platform — fast, rugged, and clear.
3. Primary Arms SLX 3-18x50mm FFP Gen II
If you’re serious about precision shooting with your 20-inch AR, the Primary Arms SLX 3-18x50mm FFP Gen II is one of the most value-packed optics available. I mounted it on my .224 Valkyrie AR build — a perfect match.
Specs
Pros
Cons
Glass & Reticle
The ACSS Athena BPR reticle provides holdovers that perfectly match 5.56 or .308 trajectories. The glass is bright, with only minor edge distortion at full magnification.
Personal Setup
I mounted it with a 20 MOA cant one-piece mount on my AR-15 upper. Zeroed at 100 yards in 7 shots, then confirmed tracking with a tall target test — it returned to zero flawlessly.
Durability
Rain, cold, and recoil didn’t faze it. After 300 rounds, no zero shift whatsoever.
Verdict:
This is the perfect match for long-range enthusiasts using the 20-inch AR platform.
4. Leupold VX-Freedom 3-9x40
For those who prefer simplicity and proven reliability, the Leupold VX-Freedom 3-9x40 is a timeless classic. It’s lightweight, rugged, and ideal for hunting or general field use with a 20-inch AR.
Specs
Pros
Cons
Performance Notes
Mounted on my .223 Wylde AR, the VX-Freedom made quick work of prairie dogs out to 350 yards. The image clarity and color fidelity are classic Leupold — sharp and vibrant.
Verdict:
Perfect for hunters or casual shooters who want dependable simplicity on their AR.
5. Arken Optics EP8 1-8x28 LPVO FFP
The Arken EP8 is one of the most underrated LPVOs I’ve tested. It’s designed for speed and clarity, yet it holds its own for precise 400-yard shots on a 20-inch AR.
Specs
Pros
Cons
Verdict:
A powerful, fast LPVO that bridges the gap between tactical and hunting optics. Perfect for shooters who want one optic that can do it all.
🧠 How to Choose the Right Scope for Your 20-Inch AR
When choosing the best optic for your 20-inch AR, focus on the intended role:
Key Features to Evaluate:
❓ FAQs
1. What magnification is best for a 20-inch AR?
For general use, 3–9x or 1–8x LPVOs are ideal. For long-range precision, go for 4–16x or higher.
2. Can I use a 5-25x scope on my AR-15?
Yes, but it’s best suited for longer barrels or AR-10 platforms with heavier calibers like .308.
3. Is an FFP scope better than SFP?
FFP is ideal for range estimation and long-distance work. SFP is easier for hunting and close-range shots.
4. What’s a good budget scope for a 20-inch AR?
The Arken EP5 and Primary Arms SLX are exceptional mid-budget options with professional features.
5. How far can a 20-inch AR shoot accurately?
With quality ammunition, expect consistent hits at 600–700 yards using a proper optic.
6. Does barrel length affect optic choice?
Yes — a longer barrel offers better velocity, which means you can use scopes calibrated for extended range.
7. What’s the best LPVO for 20-inch AR rifles?
The Vortex Strike Eagle 1-8x24 and Arken EP8 are top performers for all-around use.
🏁 Conclusion
Choosing the best scope for 20 inch AR is about balancing speed, precision, and reliability. After extensive testing, the Arken Optics EP5 5-25x56 FFP stands out for its long-range capability, while the Vortex Strike Eagle 1-8x24 dominates in versatility. Whether you’re an experienced marksman or a weekend range shooter, pairing your 20-inch rifle with any of these optics will unlock its true accuracy potential.
A high-quality scope doesn’t just enhance your view — it elevates your entire shooting experience.
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