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Monstrum

Monstrum Guardian 3-9x40 AO Rifle Scope with Parallax Adjustment | Black

  • Based on 140 reviews
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Availability: In Stock.
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Arrives Saturday, Aug 29
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Style: Guardian | 3-9x40 AO


Features

  • Adjustable 3-9 times magnification, for targeting out to 600 yards and beyond
  • An adjustable objective lens or AO - that allows for sharper focus of the target image, elimination of parallax, and range estimation
  • Aircraft grade 6061 aluminum scope body with a sealed, nitrogen-charged tube for resistance to water and fog
  • Precision 1/4 MOA/click windage and elevation adjustments with locking turrets
  • Package includes High Profile Picatinny/Weaver Scope Rings and set of flip-up lens covers

Description

The Monstrum Guardian Series of precision SFP rifle scopes provides crystal clear optics with variable power options of 3-9x, 4-12x, and 6-18x based on model selection. This makes it ideal for a wide variety of applications such as hunting and long-range applications. The adjustable objective bell allows for parallax adjustment to obtain a sharp target at any distance. The glass-etched crosshair reticle features 1 MOA per tick and 10 MOA per grouping with a total of 80 MOA per axis. The entire reticle illuminates in 5 levels of red and green for visibility in most environments.

Brand: Monstrum


Color: Black | Picatinny/Weaver Scope Rings


Style: Guardian | 3-9x40 AO


Sport: Hunting


Item Weight: 15 ounces


Material: Aluminum


Magnification Maximum: 9 x


Objective Lens Diameter: 50 millimeters


Magnification Minimum: 3 x


Compatible Devices: Rifle


Magnification Maximum: 9 x


Objective Lens Diameter: 50 millimeters


Magnification Minimum: 3 x


Compatible Devices: Rifle


Mounting Type: Weaver Mount


Reticle Type: Crosshair


Item Weight: 15 ounces


Item Display Weight: 15.04 ounces


Color: Black | Picatinny/Weaver Scope Rings


Product Style: Guardian | 3-9x40 AO


Lens Color: Black


Brand Name: Monstrum


Sport Type: Hunting


Model Name: SG3940AO


Manufacturer: Monstrum


Unit Count: 1 Count


UPC: 810088810800


Included Components: Guardian Scope, One Pair High Profile Scope Rings, One Pair Spring-Loaded Flip-up Lens Covers


Manufacturer Part Number: SG3940AO-B


Material Type: Aluminum


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, Aug 29

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

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Similar Products

Top Amazon Reviews

    • Excellent Scope
Review Image by Melissa Follett
Review Image by Melissa Follett
Review Image by Melissa Follett
Review Image by Melissa Follett
Review Image by Melissa Follett
I don’t think it is possible to get a better scope for the money. When my scope was delivered, I was amazed at the quality and features it had. Unfortunately, there was a defect in the scope where something was obstructing the view inside the opticals. I set up a return with Amazon and had a new scope delivered in 3 business days. I could have returned this scope and then bought a different one but I liked the look, the feel, the optics, the lighted reticles and the price. I also really like the lens covers as well. Mounting the scope was easy and the mounting hardware is excellent quality. This scope is perfect for my little .22 rifle and is easy to set up and sight in. The objective control and magnification controls are not the smoothest I have ever used, but the optics on this scope are quite simply amazing for the price. You really cannot go wrong with this scope! ... show more
Reviewed in the United States on June 6, 2023 by Melissa Follett
    • Looks amazing and works perfectly
The Monstrum Guardian Series AO Rifle Scope with Parallax Adjustment is an exceptional choice for shooters seeking precision and versatility. With its adjustable objective (AO) feature, it allows for precise parallax correction, ensuring clear and accurate targeting at various distances. Whether you're hunting, target shooting, or engaging in long-range competitions, this scope offers reliable performance and exceptional clarity. A must-have for any rifle enthusiast looking to elevate their shooting experience. ... show more
Reviewed in the United States on April 3, 2024 by pavel maksimenko
    • Solid scope for the price
For the price, this scope is a good value. The glass is clear, but the magnification adjuster is a little stiff but I am hoping it loosens up over time.
Reviewed in the United States on February 2, 2025 by MGS
    • Good scope.
Scope is clear and easy to move all the adjustments. I'd buy again.
Reviewed in the United States on November 7, 2025 by Susan
    • Good purchase
Works as intended but don't think your American sniper with it but its definitely worth it for a starter scope easy to install and fits perfectly for my 270 Remington
Reviewed in the United States on December 10, 2025 by Jay
    • Exactly as advertised.
Well made, clear optics, and excellent price point. Will likely buy another scope once I've had a chance to run this one down range .
Reviewed in the United States on January 13, 2025 by Patrick roberts
    • Cannot zero
Does not hold zero.
Reviewed in the United States on January 4, 2026 by Salmby
    • Good for the money
For the money; very clear. Clear and no distortion at 9x. Appears to be good quality Clock adjustment are not tactile and responsive. Takes many rotations on the elevation just to move a couple MOA. However holds zero in my savage 64 fvsr 22 long rifle
Reviewed in the United States on August 8, 2024 by craig ballurio

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