Looking to enhance your shooting with the best red dot sight for Glock 21? If your answer is yes, this is a comprehensive buying guide for you. The Glock 21 is a popular choice for home defense, target shooting, and duty purposes, and in this article, we will cover some of the best red dot sights that excel in optimizing the pistol’s performance.
Red dot sights offer an intuitive aiming solution that helps users keep both eyes open while shooting. This results in faster engagement and improved situational awareness. Furthermore, red dot sights are essential for honing shooting skills. These optics also excel in virtually all lighting conditions due to the illuminated point of aim.
What Optic Footprint Does Glock 21 Have?
Most Glock handguns feature a standard footprint for red dot sights. The footprint is compatible with a wide range of optics. The Glock 21 typically uses the Glock MOS (Modular Optic System) footprint for mounting red dot sights. The Glock MOS system is a common standard for many aftermarket red dot sights and a wide range of other accessories that enhance the precision and performance of this popular handgun.
Best Red Dot Sights for Glock 21
When selecting the best red dot sight for the Glock 21, you should carefully consider factors like durability, battery life, size, and reticle options. Since the Glock 21 is a full-size pistol, this guide will explore the top red dot sights that work exemplary with this firearm.
Let’s take a look.
1. Vortex Defender CCW Micro Red Dot Sight
Specifications
- Reticle: 3 MOA Dot
- Battery Life: 9500 Hours
- Impact Point Correction: 110 MOA (Elevation) / 105 MOA (Windage)
- Adjustment per Click: 1 MOA
- Material: Aluminum
- Weight: 0.9 oz / 26 g
- Dimensions: L: 1.6 x W: 1.1 x H: 1.0″ / L: 40.6 x W: 27.9 x H: 25.4 mm
The Vortex Defender CCW Micro Red Dot Sight is the best red dot sight for Glock 21. It is built for modern everyday carry and features a compact length for maximum concealment, reliability, and the quickness you need.
With the slim profile, this red dot sight will not add any extra bulk or width to your handgun. The crisp 3 MOA reticle aids in speedy target acquisition by offering a perfect blend of precision and speed. Furthermore, this red dot sight has a large, aspherical lens that provides a class-leading sight window for a distortion-free sight picture and truer colors.
The reticle also features a brilliant, illuminated red illumination for easy targeting, even in low light. Besides, the motion activated automatically wakes up the red dot for use and shuts down after periods of inactivity to battery life.
Regarding construction, this compact red dot sight is build with premium and high-quality components to withstand rough handling. It is also built with a fast-rack textured front face adds grip for racking slide off of any surface.
Pros
- Small, lightweight, and ideal for concealed carry
- Built with a robust construction to withstand tough conditions
- Clear optics provide a clear, crisp red dot for quick target acquisition
- Long battery life to reduce the need for frequent replacements
- Simple windage and elevation adjustments
Cons
- Lacks a night vision mode, limiting use in low-light conditions.
2. Aimpoint ACRO P-2 Red Dot Reflex Sight
Specifications
- Dot Size: 3.5 MOA
- Battery Life: 50,000 Hours
- Brightness Settings: 10
- Weight: 2.1 oz / 60 g (sight only)
- Water Resistance Level: Submersible to 115 feet (35 meters)
- Clear Aperture (mm/in): 15 × 15mm / 0.59 × 0.59in
- Size 1.9” x 1.3” x 1.2” (L x W x H)
This next generation red dot sight incorporates an improved LED emitter coupled with a higher capacity CR2032 battery to provide an astonishing five years (50,000 hours) of constant-on power. It will get you on target faster and more accurately and make every shooting expedition a success.
Designed to endure the physical forces generated by semi-automatic pistol slides, this pistol sight features a fully enclosed optical channel to protect the LED emitter. It is also tested and built to exceed the requirements of professional users by being resistant to shock, vibration, temperatures, and material stresses generated by firing over 20,000 rounds of .40 S&W ammunition.
In addition to the robust construction, the sight features a new high efficiency LED emitter which provides a sharp 3.5 MOA dot. The reticle is large enough to spot with ease without obscuring the small targets. Additionally, the protective clear glass front and rear lenses guard the advanced reflective lens system while the new digital intensity adjustment keypad provides a more distinct tactile feel when adjusting the dot intensity.
Above all, this sight can be mounted on a wide range of optics-ready handguns using adapter plates. It also has night vision compatible settings so the dot can also be turned up for use in typical nighttime environments.
Pros
- Long battery life
- Outstanding build quality
- Lightweight and multi-platform friendly
- Compactible with night vision gear
Cons
- High price point
3. Athlon Optics Midas EDC 20×16 mm Red Dot Sight
Specifications
- Reticle: 3 MOA
- Weight: 0.65 oz
- Length: 1.61″
- Center Height: 0.96″
- Obj. Lens: 20 x 16 mm
- Mount: RMSc
The Athlon Optics Midas EDC 20×16 mm Red Dot Sight is a versatile optic ideal for both tactical and recreational shooting. It excels in all weather and lighting conditions making is a valuable companion in the shooting field.
With its 20×16 mm objective lens, this red dot sight offers a clear and bright sight picture, ensuring rapid target finding and acquisition in various lighting conditions. The 1x magnification and a choice of either 3 MOA dot sizes make it suitable for close to mid-range engagements.
Furthermore, the sight is built with durability and longevity in mind. It features a rugged aluminum housing that can withstand heavy recoil and harsh environments. Additionally, it is fully weatherproof for operability in all weather conditions.
Optically, the Midas EDC’s anti-reflective coating enhances light transmission, providing a crisp and vivid reticle that improves target visibility and accuracy. Over and above that, the red dot sight is equipped with a battery-efficient design that extends its operational life, reducing the need for frequent replacements.
Another standout features of this optic is its user-friendly operation. It is highlighted by its intuitive controls and adjustable brightness settings for precision aiming in different light settings. The sights compact size and lightweight build also make it a great option for mounting on a variety of firearms without adding unnecessary bulk.
Pros
- Compact and lightweight design
- Crisp 3 MOA dot for improved accuracy
- Rugged aluminum construction withstands heavy recoil and weather
- Multiple brightness settings for use in various lighting conditions
- Easy to adjust windage and elevation
Cons
- Small lens size limits the field of view
4. Burris FastFire III Reflex Red Dot Sight
Specifications
- Reticle: 3 MOA Dot
- Objective Lens Diameter: 21mm
- Brightness settings: 3
- W/E Travel at 100 Yds: 190
- Adjustment per Click: 1 MOA
- Length: 1.9 in
- Weight: 1.5 oz
The FastFire 3 is the best red dot sight for Glock 21 for those on a tight budget. It comes at a price that is easy on the wallet but does not cut any corners on performance and reliability.
This red dot sight is both light and tough, ensuring it won’t compromise gun balance or handling. Its compact build makes it versatile for mounting on guns using Burris mounting systems. Furthermore, it is backed by the Burris Forever Warranty so it is a reliable companion for years to come.
The aiming point of this red dot sight is a 3 MOA reticle. The automatic brightness sensor adapts to environmental conditions, providing a bright red dot for fast target acquisition. Additionally, it offers three manual brightness settings, giving control in various lighting situations
Construction-wise, the sight has a shockproof design to withstand punishing recoil and a waterproof construction to ensure performance in various conditions. It is also built with a battery access that is conveniently located on the top of the sight so changing the batteries is a breeze. Besides, there is an automatic time-out feature that ensures an extended battery life of up to 5 years.
Pros
- Long battery life and convenience access
- Durable and shockproof construction
- Crisp and accurate 3 MOA reticle
- Automatic brightness adjustment
- Compact, ultra-light, and multi-platform friendly
Cons
- Only 3 brightness settings for the reticle
5. C-MORE RTS2R Red Dot Sight
Specifications
- Reticle: 3 MOA Dot
- Objective Window Size: 25.76 x 22.01 mm
- Brightness settings: 10
- Battery Life: 100000 hours
- Adjustment per Click: 1 MOA
- Length: 1.275
- Weight: 1.16 oz
When it comes to performance and value, it is hard to go wrong with the C-MORE RTS2R Red Dot Sight. It comes ready to mount right out the box and the included mount is perfect for Weaver or Picatinny rail bases, and can easily be removed for direct mounting using a custom mount.
The highlight of this sight is the large field of view. It provides a spacious, unobstructed sight picture where the red dot hovers on the sight line, illuminating the point of impact on the target allowing for fast target acquisition. This aids in rapid target acquisition in all scenarios.
More importantly, the RTS2 includes a CR2032 lithium battery, lasting between 600 – 10,000 hours depending on brightness level and usage. The battery is housed in a side loading removable tray, eliminating the need to dismount and re-zero the sight.
Regarding construction, the sight is built from rugged aircraft grade 6061T6 aluminum to weather abuse and ensure long-term durability. It also features a large performance coated glass lens and weighs 1.16 oz only so it won’t come in your way of shooting.
Pros
- Ease of use
- Unmatched versatility
- Lightweight and compact design
- Robust and reliable construction
6. Trijicon RMR Type 2 1×1 MOA Adjustable LED Reflex Sight
Specifications
- Reticle: 1 MOA Dot
- Objective Window Size: 0.83 x 0.63 in
- Brightness settings: 8
- Battery Life: 4 Years at setting 4
- Adjustment per Click: 1 MOA
- Length: 1.8 inches
- Weight: 1.2 oz
Trijicon is renowned for its rugged and quality optics and the Trijicon RMR Type 2 1×1 MOA Adjustable LED Reflex Sight is not any different. This compact optic harbors a wide range of advanced features to enhance your shooting precision.
Firstly, the sight features an automatic brightness mode and easy push buttons for eight adjustable brightness settings including 2 nv and 1 super bright. This makes it ideal for shooting in all lighting conditions. Besides, it automatically adjusts aiming dot to ambient lighting conditions after 16.5 hours, conserving the battery life.
Durability is another feature that makes it the best red dot sight for Glock 21. It is crafted with a dependable electronic design and ruggedized battery contacts to ensure performance and survivability in harsh environments. Furthermore, the military-grade aluminum alloy forged housing shape diverts force of impact away from the lens, greatly increasing its durability
Above all, the red dot sight features a button lockout mode that sets RMR into automatic mode. This ensures that inadvertent button pushes do not cause a loss of aiming solution.
Pros
- Outstanding durability
- Compatible with night vision gear
- Ease of use
- Long battery life
Cons
- Comparatively expensive
7. VOTATU PMD504 Multiple Reticle Red Dot Sight
Specifications
- Reticle: 2 MOA dot and 62 MOA circle
- Brightness settings: 10
- Eye Relief: Unlimited
- Battery Life: 50,000 Hours
- Windage/Elevation Movement: +/- 45 MOA/ Total 90 MOA Rang
- Length: 1.9 inches
- Weight: 35g/1.23oz
Lastly, we have the VOTATU PMD504 red dot sight. The sight is crafted with quality and user-friendly features to accommodate all users, including beginners.
It features three reticle options ( the classic 2 MOA dot, the 62 MOA circle and their combination circle-dot reticle ) that allows for fast target acquisition. You can tailor the reticle to match your shooting needs. Besides, the 10 brightness settings make the optic ideal for use in different lighting conditions.
To help the reticle serve its purpose are fully multi-coated lenses that fight glare and increase light transmission and clarity in any environment.
Furthermore, the red dot sight is built to last. It is housed in durable yet lightweight aircraft-grade aluminum for use in any environment. Additionally, it is IPX7 waterproof and fog-proof to be operable even in adverse weather conditions.
This red dot sight also has a side-loading battery compartment that allows for quick battery replacement without having to remove the sight from the firearm.
Pros
- Long battery life
- Convenient battery access
- Multi-reticle system
- Durable aircraft-grade aluminum construction
- Lightweight and easy to install
Cons
- Not compatible with night vision gear
Best Red Dot Sight for Glock 21 Buying Guide
Choosing a red dot sight for Glock 21 is not something you do in a whip. Consider the following key criteria to ensure optimal performance and compatibility:
Durability and Build Quality
The durability of red dot sights is determined by their build quality. Ensure the red dot sight is made from durable materials like aluminum or high-grade polymers. Additionally, the sight should be shockproof, waterproof, and fog-resistant for use in rugged conditions and all weather conditions.
Mounting Compatibility
Not all red dot sights available on the market are compatible with Glock 21. Check if the red dot sight is compatible with your Glock 21’s mounting system. Some red dot sights may require a specific adapter plate or a modified slide (e.g., MOS system or aftermarket slides) to mount properly.
Size and Weight
The next thing to consider is size and weight. A compact and lightweight red dot sight will better complement the Glock 21’s balance and weight distribution. You should also consider micro or sub-compact red dots that won’t add significant bulk to the firearm.
Reticle Size and Type
Reticle sizes between 2 MOA to 6 MOA are generally good for handguns and Glock 21 is not any different. These reticles offer a perfect balance between precision and speed. Some modern sights offer multiple reticle patterns (dot, circle-dot), giving you more flexibility depending on the shooting situation.
Battery Life
Most red dot sights for handguns are powered by battery. Choose a red dot sight with long battery life, ideally in the range of 50,000 hours. The best red dot sight for Glock 21 should also have auto-off features or solar backups that further enhance battery efficiency.
Ease of Use
A red dot sight that is built with ease of use in mind is the best for all shooters. When making your selection, look for features like easy-to-adjust windage and elevation controls. Moreover, the brightness settings should be adjustable for different lighting conditions, preferably with multiple levels for you to choose from.
Lens Quality
Opt for a red dot sight that is built with high-quality lens. It will provide a clear and wide field of view with good light transmission, reducing parallax and distortion. Anti-reflective coatings on the lens are also important for enhance visibility in bright sunlight or low-light situations.
Price
The price of the best red dot sights for Glock 21 varies from one product to the other. Balance your budget with the features you require. Higher-end models tend to offer better durability and features, but there are a myriad of reliable mid-range options as well.
Read Also
- 6 Best Red Dots for Glock 17
- 5 Best Pistol Red Dot for Astigmatism
- 5 Best Red Dot for Canik Mete SFT
FAQs
- Does the Glock 21 require a specific mounting system for a red dot sight?
If your Glock 21 is MOS-ready, it comes with a slide cut designed for mounting optics. However, if it’s not MOS, you will need to either get the slide milled or use an adapter plate to mount the red dot.
- What is the ideal dot size for a Glock 21 red dot sight?
A 2-3 MOA dot is typically ideal. It offers a balance of precision for longer shots and quick target acquisition for close-up scenarios.
- Is it worth putting a red dot on Glock 21?
Yes. Putting a red dot on Glock 21 makes it easy for you to acquire targets accurately in different lighting conditions. A red dot sight also enhances your speed in shooting and increases your situational awareness by allowing shooting with both eyes open.
Final Words
Investing in the best red dot sight for Glock 21 will substantially improve your accuracy and help you get the most out of this versatile handgun. All the red dot sights we have mentioned in this guide have all the basic features you need to hone your skills and become a better shooter. So, look at the attributes that make each model a good purchase and choose accordingly.