Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane Review

My Journey with the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane

For over a decade, my world has revolved around gear that performs when it counts, whether it’s in the dusty confines of a workshop, the sterile environment of a lab, the unpredictable outdoors, or the focused intensity of a field test. When the need arose for a versatile optic that wouldn’t break the bank, my attention turned to the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane. This particular model promised a blend of magnification, clarity, and essential features at a price point that immediately piqued my interest.

The catalyst for this exploration was a shift in my rimfire training regimen. Previously, I relied on a Simmons 22 Mag scope for my .22 LR rifle, which served its purpose but left me wanting more in terms of consistent clarity and ease of parallax adjustment. I was looking for a step up, something that offered better target acquisition without demanding a premium price. This search led me to explore various entry-level to mid-range optics.

Upon unboxing, my initial impression was one of solid, no-nonsense construction. The matte black alloy body felt robust, and the adjustment turrets offered a satisfying, albeit not overly precise, tactile click. It certainly looked the part, exuding a readiness for use rather than delicate handling. Compared to the Simmons I was replacing, it already felt like a more substantial piece of equipment.

This particular model presented itself as a compelling option, offering a decent magnification range and the crucial adjustable objective (AO) feature. The promise of better visual acuity, especially at varying distances, was the primary draw. My hope was that this Nikko Stirling optic would bridge the gap between basic functionality and the more advanced capabilities I’d come to expect from higher-end scopes.

Real-World Testing: Putting the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane to the Test

My primary testing ground for this optic was within the controlled environment of an indoor range, specifically for .22 LR Competition Machine Pistol (CMP) matches. This setting demanded quick target acquisition and precise shot placement at distances ranging from 25 to 100 yards. The ability to adjust for parallax was crucial here, as varying shooting positions and distances required consistent focus.

During these indoor sessions, the scope performed admirably. The 3-9x magnification range proved versatile enough for the distances involved, allowing me to easily distinguish targets and fine-tune my aim. The 40mm objective lens gathered sufficient light for the ambient conditions, and the multi-coated lenses did a respectable job of minimizing glare. I found myself frequently adjusting the parallax using the adjustable objective (AO) feature on the bell, which proved to be a significant improvement over my previous scope.

With extended use over several months and numerous range days, the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane has held up remarkably well. The overall construction remains solid, with no signs of loosening or internal shifting. The matte finish has resisted minor scuffs and scrapes that are inevitable with regular handling.

Maintenance has been straightforward; a quick clean with a lens cloth and appropriate cleaning solution is all that’s needed to keep the lenses pristine. The nitrogen-filled internals have also done their job, preventing any fogging issues even during brief periods of temperature fluctuation when transporting the rifle between my vehicle and the range. Compared to some budget optics that can quickly develop internal dust or lose their zero, this model has demonstrated admirable reliability.

First Use Experience

My first outing with this optic was at a local indoor range, where I mounted it on a Ruger 10/22 Takedown rifle. The initial setup was straightforward, aided by the fact that it came with 3/8” mounts, which were a convenient addition. Adjusting the magnification from 3x to 9x felt smooth, and the focus ring on the eyepiece provided clear, sharp images.

The adjustable objective (AO) was immediately noticeable as a key benefit. Being able to dial out parallax at different distances meant my point of aim remained consistent, a critical factor for competitive shooting. The click values on the turrets, while not the finest, were adequate for making sight adjustments between stages.

Extended Use & Reliability

After several months of consistent use, this scope has become a reliable component of my rimfire setup. It’s been subjected to the usual bumps and jolts of transporting a rifle, and crucially, it has maintained its zero perfectly. The shockproof and waterproof ratings, while tested only by incidental exposure to light moisture and the general rigors of range bag use, seem to be well-justified by its continued robust performance.

The 1-inch tube diameter is standard and compatible with a wide array of rings, though the included mounts were perfectly functional. I haven’t experienced any degradation in optical clarity or brightness over time. The Second Focal Plane (SFP) reticle has remained crisp and in place, a testament to the scope’s internal construction.

Breaking Down the Features of the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane

This optic packs a surprising number of practical features into its accessible price point. The Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane is designed for versatility and ease of use, making it a compelling choice for a variety of rimfire and light-caliber applications. It’s a no-frills optic that focuses on delivering essential performance.

Specifications

The core specifications highlight its utility. The 3-9x magnification offers a good balance between wide-field observation at 3x and more detailed aiming at 9x. The 40mm objective lens provides a decent light-gathering capability for its class.

• Manufacturer: Nikko Stirling – A known name in the optics market, often associated with reliable, value-oriented products.
• Magnification: 3 – 9 x – This variable magnification is ideal for general-purpose shooting, covering close-range and medium-range engagements. It’s a classic range that suits many applications.
• Objective Lens Diameter: 40 mm – A standard size that offers a good compromise between light transmission and overall scope size and weight.
• Tube Diameter: 1 in – This common tube size ensures compatibility with a vast selection of mounting rings and bases available on the market.
• Reticle Focal Plane: Second Focal Plane (SFP) – In an SFP scope, the reticle size remains constant regardless of magnification, meaning subtensions (like MOA markings) are only accurate at a specific magnification setting, typically the highest. This is common for this price point and general-purpose use.
• Parallax Adjustment: 10 yds to infinity (via AO bell) – This is a standout feature for its price class. The adjustable objective allows for precise focus adjustment, eliminating parallax errors which is crucial for accuracy, especially at lower magnifications or varied distances.
• Eye Relief: 3.3 in – This provides a comfortable shooting experience, allowing for consistent sight picture acquisition without the risk of scope bite, especially on lighter recoiling firearms.
• Weight: 380 g – This is a relatively lightweight optic, making it a good choice for firearms where weight is a consideration, such as .22 LR rifles or lightweight hunting carbines.
• Adjustment Click Value: 1/4 MOA – The turrets make 1/4 Minute of Angle adjustments per click, which is standard and provides reasonable precision for sighted adjustments.
• Reticle: 1/4 MOA – The reticle itself uses standard MOA subtensions, which are widely understood and easy to work with for dialing adjustments.
• Finish: Matte – The matte black finish is non-reflective, which is essential for not giving away your position in the field and also reduces glare during use.
• Optical Coating: Multi-Coated Lenses – This enhances light transmission and reduces internal reflections, leading to a brighter and sharper image, especially in less-than-ideal lighting conditions.
• Weather Resistance: Waterproof, Shockproof, Fogproof – These are vital features for any optic intended for real-world use. They ensure the scope can withstand various environmental conditions without internal damage or performance degradation.

Performance & Functionality

The primary function of this optic is to magnify distant targets and provide a clear aiming point. In this regard, the Nikko Stirling Mountmaster 3-9×40 AO generally succeeds. The magnification range is well-suited for typical plinking, small game hunting, and competitive rimfire shooting.

Its main job is to deliver a clear, magnified image, and it does this competently. The adjustable objective (AO) is the star feature here, allowing the shooter to achieve a parallax-free image at virtually any distance from 10 yards to infinity. This significantly improves accuracy by ensuring the reticle stays aligned with the point of aim.

However, the optical clarity, while good for the price, isn’t going to rival premium scopes. In very low light, edge-to-edge sharpness might slightly diminish, and chromatic aberration can become noticeable if you look for it. But for the intended use cases, the performance is more than adequate.

Design & Ergonomics

The design is functional and straightforward. The 1-inch matte black alloy body tube is robust and has a utilitarian appearance. The knurling on the magnification ring and the AO adjustment bell is aggressive enough to provide a secure grip, even with gloves on.

The turrets are protected by screw-on caps, which is standard. Removing them reveals exposed turrets that can be zeroed by lifting and rotating. The eye relief of 3.3 inches is generous, offering a comfortable shooting experience and making it suitable for a wide range of rifle actions.

Durability & Maintenance

This scope is built to withstand a fair amount of abuse. The shockproof rating means it can handle the recoil of most rimfire rifles without issue, and the waterproof construction ensures it won’t be damaged by rain or a quick dunk. Nitrogen filling is a key feature for its fogproof capabilities, preventing condensation from forming on the inside of the lenses.

Cleaning is simple: use a lens cleaning solution and a microfiber cloth for the lenses. The body can be wiped down with a damp cloth. There are no complex maintenance requirements, making it ideal for users who want a reliable optic that doesn’t demand extensive care.

Accessories and Customization Options

A notable positive is that the scope often comes supplied with 3/8” mounts. These are perfectly functional for many rimfire rifles and save the buyer from an immediate additional purchase. While these are basic rings, they do the job effectively for lighter recoil applications.

Beyond the included mounts, the 1-inch tube makes it highly compatible with aftermarket rings from countless manufacturers if you wish to upgrade for specific mounting heights or styles. The Second Focal Plane (SFP) reticle means you aren’t looking for specialized reticle-based ranging tools, keeping the scope’s function centered on magnification and aiming.

Pros and Cons of the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane

Who Should Buy the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane?

This optic is an excellent choice for the budget-conscious shooter looking for a reliable and functional scope for their rimfire rifle, such as a .22 LR or .22 Magnum. It’s particularly well-suited for those involved in entry-level competitive shooting where parallax adjustment is beneficial, like rimfire CMP matches or informal target practice. It’s also a solid option for small game hunters who need a versatile magnification range and the ability to ensure a clear sight picture at varying distances.

Anyone seeking an affordable upgrade from a basic factory scope will find this model a significant improvement. Those who demand the absolute best in optical clarity in challenging low-light conditions or require highly precise, holdover-based long-range shooting with an SFP reticle might need to consider higher-tier options. For its intended audience, however, it’s a fantastic fit.

Essential complementary items would include a quality set of rings if the included ones don’t meet specific mounting needs, and of course, the firearm it will be mounted on. A simple lens cleaning kit is also advisable to maintain its performance.

Conclusion on the Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane

The Nikko Stirling Mountmaster 3-9×40 AO, 1in Tube Rifle Scope, Second Focal Plane stands out as a genuinely capable optic that punches well above its weight class. Its combination of a versatile magnification range, critically important adjustable objective, and robust build quality makes it a superb value proposition. While it doesn’t offer the pristine optical performance of premium brands, it provides more than enough clarity and functionality for its target audience.

For the price point, the durability and features like waterproof and shockproof construction are highly commendable. It’s the kind of optic that instills confidence, knowing it will perform when you need it to, and the included mounts sweeten the deal considerably.

I would wholeheartedly recommend this scope to anyone looking for a dependable, feature-rich optic on a budget, particularly for rimfire applications or light-caliber rifles. It’s a practical, no-nonsense choice that delivers on its promises and then some. If you’re stepping up your shooting game and need a reliable performer without draining your wallet, this Nikko Stirling model is definitely worth serious consideration.