AR-15 Accessories, AR-15 Basics, Optics
How to Mount a Red Dot Optic on Your AR-15
Sep
The proper steps on how to mount a red dot optic on your AR-15 are not difficult, but its something you’ll want to take your time with and do properly. It’s a bit easier than mounting an LPVO, but its just as important to get right to ensure that you have a true and consistent zero. Red dot sights have revolutionized modern shooting, offering a return to instinctive, threat-focused aiming. Provided they are mounted correctly, these optics enhance speed, accuracy, and situational awareness by allowing shooters to keep both eyes open and focus on the target rather than the front sight. If you’re considering adding a red dot to your AR-15, this guide will walk you through why you should and how to mount it for optimal performance.
Benefits of Red Dot Optics
If you’re reading this guide, there’s a good chance we don’t need to sell you on the obvious benefits of why you need a red dot on your AR, but just in case, the addition of a properly mounted red dot on your AR is a true game changer. Why?
- Rapid Target Acquisition: Red dots allow for quick sight picture and faster engagement of multiple targets.
- Improved Accuracy: Many shooters who mount a red dot see immediate improvements in their shooting, especially in dynamic scenarios.
- Versatility: Suitable for various applications from home defense to competition shooting.
- Simplicity: The single aiming point is intuitive and easy to use, particularly under stress.
Mount a Red Dot – Safety First, Readiness Always
Here’s the section where we remind you to be safe when working with your AR as you mount a red dot. Double check that the gun is safe and clear. This should go without saying, but we’ve heard too many stories of folks working on optics and accessories on a hot gun with one in the chamber by accident. Please take a second and double check before we move forward. As a reminder:
- Always treat the firearm as if it’s loaded.
- Keep the muzzle pointed in a safe direction at all times.
- Ensure the safety is engaged before handling.
- Clear the firearm: Remove the magazine, rack the charging handle, and visually and physically inspect the chamber to confirm it’s empty.
Mount a Red Dot – Workspace Setup
There are going to be a few small parts, screws, etc., involved as we mount our red dot. Set up in a well-lit, clean area with ample space. Use a soft cloth or mat to protect your firearm and optic.
Optic Inspection
It’s a good idea to do some basic inventory straight out of the box. There’s not a zero percent chance that something was left out when the manufacturer boxed up your optic to be shipped to you. Make double sure right off the bat that what should be there, is there.
- Check all parts against the manufacturer’s list.
- Inspect for any visible damage or defects.
- Familiarize yourself with each component.
- Review the instruction manual thoroughly.
Battery Check
Before getting the optic installed, it makes some sense to quickly check that this optic works and you were not sent a lemon. This is as simple as putting in the battery and verifying that the optic works.
- Insert the provided battery, ensuring correct polarity.
- Power on the optic and cycle through its settings.
Tool Preparation
Gather all necessary tools:
- Appropriate screwdrivers or Allen keys if they are not included
- Torque wrench (if specified by the manufacturer)
- Thread-locking compound (if recommended)
- Lens cleaning supplies
Mount a Red Dot – A Step-by-Step Guide
Mount Selection
Choose a mount compatible with both your optic and rifle. For AR-15s, Picatinny mounts are standard, but consider M-Lok or quick-detach options based on your needs. Some optics, like the Aimpoint T2, require specific mounts, while others may attach directly to the rail.
Before beginning the process to mount a red dot, it’s crucial to understand that red dot sights may or may not come with their own mounts. This is an important detail you should have researched during the buying phase. Some optics, like many Holosun, Vortex or Sig Sauer models, come with integral mounts designed for AR-15 platforms. Others, particularly high-end options like Aimpoint, often require separate mounts purchased specifically for your rifle.
It’s a common mistake for newcomers to mount a red dot directly on the rail, but this is typically not feasible or advisable for AR-15s. A proper mount serves two critical functions: it provides the necessary height to align the optic with your line of sight over the AR-15’s taller front sight, and it offers a secure attachment point designed to withstand the recoil forces of the rifle.
An ARs Design Quirk That Makes Mounts a Necessity
ARs have a stock that sits in line with the top of the receiver, which means you’ll need a higher optic mount to achieve a comfortable and natural shooting position. Without a high mount, you’d have to press your face uncomfortably low against the stock, causing strain on your neck and throwing off your alignment. In contrast, lower mounts are typically designed for firearms with different stock configurations, like shotguns, where the height of the mount matches the natural line of sight without requiring such adjustments. Using the right height mount ensures better ergonomics and faster target acquisition on your AR.
Without the correct red dot mount, your red dot may sit too low for comfortable use, fail to hold zero, or even become damaged during firing. Always ensure you have the appropriate mount for your specific red dot and AR-15 combination before proceeding with installation.
Optimal Placement
Consider your shooting style and the optic’s intended use when deciding where to mount a red dot:
- General Use: Mount the red dot in the forward portion of the receiver.
- Competition or Close-Range Use: Some shooters prefer mounting the optic as far back as possible, just in front of the charging handle.
- Long-Range or Magnified Use: A more forward mounting position might be preferable if using a magnifier or frequently engaging distant targets. You’ve got to make sure you have enough room for the magnifer that will sit to the rear of your red dot.
Mount Preparation
Follow the instructions included with your mount and optic, but typically you will do this: Apply a small amount of thread-locking compound to the screws. Use a medium-strength variant (often blue in color) rather than a permanent one.
Optic Positioning
Place the red dot sight on the chosen spot on your rifle’s rail. If you’re unsure, start with a forward position on the receiver. One of the biggest mistakes people make when mounting a red dot optic to their AR is bridging the optic between the upper receiver and the handguard.
This is a critical error because the upper receiver and handguard are separate components that can move independently due to heat, pressure, or flexing during use. By mounting the optic across both, any shift or movement in the handguard will affect the alignment of the optic, causing a loss of zero and compromising accuracy. Always ensure the optic is mounted fully on the upper receiver to maintain a consistent point of aim and avoid issues with zero retention.
As long as you are not bridging the upper with the handguard, mount a red dot optic further forward on the rail significantly enhances your field of view, allowing for a clearer and more comprehensive picture of your surroundings. By positioning the red dot optic closer to the front of the upper receiver, you reduce the amount of clutter in your peripheral vision, giving you a better, more focused sight picture through the optic itself.
This forward placement also promotes greater situational awareness, enabling the shooter to maintain a clearer view of what’s happening outside the optic. Having a broader field of view not only improves target acquisition but also helps you stay more aware of your environment, which is crucial in both defensive and tactical scenarios. Keeping the optic far enough forward ensures a balance between fast target engagement and overall situational awareness.
Securing the Optic
Push the red dot optic forward firmly against the rail before tightening the screws. Tighten the screws to the manufacturer’s recommended torque specifications using a torque wrench.
Why do this? When the AR-15 recoils, inertia causes optics and other accessories to shift forward. If your optic isn’t securely butted against the rail, this movement can gradually cause it to slide forward with each shot. Over time, this creeping movement can result in a loss of zero, affecting your accuracy. To prevent this, ensure that your optic and any other accessories are mounted firmly against the rail, eliminating any potential for movement during recoil.
Alignment and Zeroing
Once you mount a red dot optic, confirm your red dot is properly aligned. If using backup iron sights, ensure the dot co-witnesses correctly. Zero your optic at your preferred distance. A 50-yard zero is often considered ideal for a red dot optic on an AR because it provides a versatile balance for both close-quarters engagements and mid-range accuracy.
With a 50-yard zero, the point of impact is nearly identical at 200 yards due to the trajectory of most common AR calibers like 5.56mm. This means your rounds will hit close to your point of aim from 0 to 200 yards, minimizing the need for holdovers in typical defensive or tactical scenarios. However, if you’re using a 2 MOA red dot, zeroing at 100 yards is also a practical option, especially if you expect to engage targets at longer distances. The smaller 2 MOA dot allows for greater precision at extended ranges, where the dot size will cover less of the target, providing more accuracy for those further shots. Both zeroing methods have their merits depending on your specific application, but the 50-yard zero offers a more flexible solution for most situations.
Maintenance Checks
Periodically check the tightness of your mount screws, especially after initial use.
How to Mount a Red Dot Optic on Your AR-15 – Conclusion
Adding a red dot sight to your AR-15 can significantly enhance your shooting experience. By carefully considering your optic’s placement and following proper mounting procedures, you can maximize the benefits of your red dot sight.
Remember, the “best” mounting position is the one that works for you and your shooting needs. Don’t be afraid to experiment with different placements to find what feels most natural and performs best for your typical shooting scenarios.
Whether you’re a competitive shooter, a home defender, or a recreational enthusiast, a properly mounted red dot can help you make the most of your AR-15, bringing you back to a more natural, instinctive way of aiming that aligns with our innate shooting instincts.
Mounting a red dot sight is a process that combines precision with personal preference. Take your time, follow these steps, and don’t hesitate to make adjustments as you become more familiar with your setup. Always prioritize safety, take your time with the mounting process, and enjoy the enhanced performance that a well-mounted red dot sight can bring to your AR-15.
