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Monstrum

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

  • Based on 1,371 reviews
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Availability: In Stock.
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Arrives Saturday, May 23
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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

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


Night vision: No


Reticle Type: Crosshair


Color: Black | Picatinny/Weaver Scope Rings


Product Style: Guardian | 3-9x40 AO


Material Type: Aluminum


Brand Name: Monstrum


Sport Type: Hunting


Manufacturer: Monstrum


UPC: 810088810800


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


Item Weight: 15 Ounces


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, May 23

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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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
    • 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
    • Nice and solid
I like the clear optics and solid construction! This scope is crystal clear and built well. The cross hair is nice and crisp but kinda thin compared to a standard duplex. The illumination is good also.. overall I’m impressed!!
Reviewed in the United States on October 5, 2023 by michael mcneese
    • 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
    • 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
    • 2 for 2 Defective Scopes
Review Image by Audrey Jarmin
I purchased this scope and initially received a defective product. The illumination turret would not turn at all no matter the pressure I applied and I was concerned that I would physically damage the scope. I processed a return and had them send me another scope. The second scope showed up and the illumination turret turned as it should. However, neither the green nor red illuminated on the fourth brightness setting. The illumination worked on all other setting levels, both green and red, but was inexcusably uneven across the reticle crosshairs. I’ve had reasonably good success with Monstrum’s scope rings, mounts, and other accessories, but in the future I will direct my purchasing dollars towards other manufacturers for better quality optics. ... show more
Reviewed in the United States on December 10, 2024 by Audrey Jarmin
    • 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
    • Good value
For a cheap scope option it's better than the rest. Highly suggest.
Reviewed in the United States on April 6, 2025 by Steven Harville

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