Introduction
The world of handguns is undergoing a revolution. The rise of red dot sights (RDS) on pistols has transformed how shooters aim, offering faster target acquisition, improved accuracy, and enhanced situational awareness. This technology is becoming increasingly prevalent in competitive shooting, law enforcement, and even for concealed carry, with enthusiasts embracing the advantages these optics provide. However, with this growth comes a degree of complexity. Choosing the right optic mount can be daunting, especially when considering the wide array of options available. Confusion surrounding these mounting systems is a common hurdle for those looking to embrace the benefits of a pistol-mounted red dot.
This article aims to provide clarity by diving deep into two primary methods for mounting optics on Glock pistols: the Glock MOS footprint and the Trijicon RMR footprint. We’ll explore the intricacies of each system, comparing their features, advantages, and disadvantages. Our objective is to empower you, the shooter, to make an informed decision, selecting the optic mounting solution that best suits your needs, skill level, and shooting goals. We’ll dissect the core components of each system, examining the critical factors that influence performance and long-term reliability. By the end of this piece, you’ll have a comprehensive understanding of the Glock MOS footprint and the Trijicon RMR footprint, equipping you to confidently choose the setup that will optimize your shooting experience.
Understanding Optic Footprints
Before we delve into the specifics, let’s establish a crucial foundation: the concept of an optic “footprint.” In the realm of pistol optics, a footprint refers to the physical dimensions of the interface between the optic and the slide (or mounting system). Essentially, it’s the precise arrangement of screw holes and the shape of the mounting surface, defining how an optic physically attaches to the pistol. This design directly impacts the optic’s compatibility and dictates which red dot sights can be successfully installed on a particular firearm.
Footprints are paramount because they govern the ease with which you can mount an optic. They ensure that the holes align, the screws engage correctly, and the optic sits securely on the slide. They also influence the overall profile of the setup, impacting how high the optic sits above the bore (height over bore), and the degree of integration with the firearm. Choosing an optic with the wrong footprint renders the optic unusable on your pistol. This requires you to have to select the proper footprint and then shop for an optic within those design limitations. The industry has recognized the need for standardization, and certain footprints have gained widespread acceptance.
The two primary footprints that will be addressed in this article are the Glock MOS footprint and the Trijicon RMR footprint.
The Glock MOS System
Glock’s Modular Optic System (MOS) represents a widely adopted approach to integrating red dot sights into their pistols. This system is intended to provide broad compatibility by utilizing a series of interchangeable adapter plates that mate with the slide. These plates are designed to accommodate various optic footprints.
The MOS system’s history began with Glock’s desire to offer a factory-ready solution for mounting optics. This evolution aimed to cater to the growing demand for red dots without requiring extensive slide modifications. The system was designed to offer flexibility, allowing owners to easily swap between different optics or remove the optic entirely for iron sight usage.
Pros of the Glock MOS System
One of the significant advantages of the Glock MOS system is its inherent versatility. By employing adapter plates, the MOS system accommodates a wide variety of optic footprints. This means that owners are presented with a broader selection of optics to choose from. This modular approach reduces the need for specific slide modifications, potentially simplifying the installation process. The initial cost may be less in some instances, given that many MOS-compatible optics are relatively affordable and that owners can buy different plates to move between optics. This is often attractive to shooters who want the option to easily try different red dot sights without committing to permanent modifications.
Cons of the Glock MOS System
Despite its advantages, the Glock MOS system is also linked to several drawbacks. Adapter plates can introduce a potential weak point in the mounting system. Because the optic sits on the plate, there is a slight increase in the height of the optic, leading to a higher height over bore. The plate and the additional screws can create instability and the risk of screws working loose over time. The MOS adapter plates can also come under significant stress during recoil. In addition, some users have reported problems with adapter plates failing under heavy use, particularly with larger and heavier optics. Many shooters have expressed preference for direct-milled slide cuts for their RDS.
The Trijicon RMR Footprint
The Trijicon RMR (Ruggedized Miniature Reflex) footprint represents a more direct and, in many cases, a more robust mounting solution. This footprint derives its name from the popular Trijicon RMR optic itself. Its design allows for a direct mount to the slide, most often by either cutting a slide or using a slide designed with an RMR footprint.
The RMR footprint gained its popularity with the Trijicon RMR. Since its release, many other manufacturers have created optics to match the same footprint. This direct mounting method generally eliminates the need for adapter plates, making the interface between the optic and the slide more solid and stable.
Pros of the RMR Footprint
The primary advantage of the RMR footprint is the increased stability and durability that comes with direct mounting. The optic sits closer to the slide, reducing the potential for movement or loosening caused by recoil. Because the optic sits directly onto the slide, the height over bore is reduced, further enhancing the handling characteristics of the pistol and providing a more consistent sight picture. Direct mounting eliminates the potential for plate failures, making the system inherently more reliable. Many users report exceptional performance and dependability with RMR footprint systems.
Cons of the RMR Footprint
Direct mounting, however, requires either the purchase of a slide that has been cut to accept the RMR footprint or modification to your existing slide by a qualified gunsmith. Modification can require milling or some other process to create the proper channels and screw holes. Because of the precision required, these services typically involve professional gunsmithing, which increases the initial cost.
Direct Comparison: Glock MOS vs. RMR Footprint
Let’s directly compare the Glock MOS footprint and the Trijicon RMR footprint across several key areas:
Compatibility
The MOS system, by design, is meant to offer broader optic compatibility due to its use of adapter plates. This means that you’re likely to find adapter plates for a wide range of optics. The RMR footprint is less versatile by design; it dictates that the optic must use the RMR footprint. That said, the popularity of the RMR footprint has driven numerous manufacturers to create optics specifically designed to fit it. This makes more choices available than ever before.
Mounting
The MOS system involves mounting the optic to the adapter plate, then attaching the plate to the slide. This typically involves tightening a couple of screws. The RMR footprint, on the other hand, requires the optic to be directly mounted to the slide or the use of a slide designed with the proper footprint. This often entails precise screw alignment and torqueing for a more secure attachment.
Stability and Durability
The RMR footprint generally wins in this category. The direct-mount approach minimizes the risk of movement. This is a significant advantage over adapter plates, which can be prone to shifting under recoil or heavy use.
Height Over Bore
The RMR footprint provides a lower profile. Direct mounting typically positions the optic closer to the slide, thereby decreasing the height of the optic above the bore axis. The Glock MOS system, utilizing adapter plates, often raises the optic, increasing the height over bore, and potentially affecting target acquisition and alignment.
Cost
The MOS system may initially appear less expensive. You might purchase an optic that fits with an existing adapter plate, or be required to buy an adapter plate. However, the long-term cost of the RMR system can be offset if you choose to go with a direct mount.
Reliability
Reliability is a crucial factor. The RMR footprint often excels in this area due to the absence of adapter plates. This design mitigates the risk of plate-related failures. The Glock MOS system, despite its convenience, introduces a potential failure point.
Choosing the Right Footprint for You
Selecting the appropriate optic mounting system is a personal decision, influenced by your individual preferences and priorities. Here are some factors to consider:
Intended Use
Your primary use case can guide your decision. If you intend to use your pistol for competition shooting, where speed and accuracy are paramount, then the direct mount option may be attractive. Duty carry requires supreme reliability, which is another compelling argument for the more robust RMR footprint. For recreational shooting, concealed carry, and range practice, the advantages of either option are more nuanced.
Budget
How much are you willing to spend? Consider the total cost, including the optic, adapter plates (if applicable), slide milling (if required), and any potential professional installation fees. The MOS system can be initially cheaper, but the long-term costs may vary. The RMR footprint requires a more substantial upfront investment.
Technical Expertise
Do you have experience installing pistol optics, or are you comfortable with potentially complex modifications? If you prefer a simpler setup and are less confident in your technical skills, the MOS system might be a better choice. However, both options can require professional gunsmithing, especially if you plan to have the slide milled for an RMR footprint.
Optic Selection and Future Upgrades
Do you have a specific optic in mind? Ensure that the optic footprint is compatible with your chosen mounting solution. Consider the long-term implications.
Decision Guide
If you are prioritizing broad compatibility and easier initial setup, the Glock MOS is a good option.
If you are seeking increased stability, durability, and are willing to invest in slide modifications or a dedicated slide, the RMR footprint is likely best.
Conclusion
The Glock MOS footprint and the Trijicon RMR footprint each present unique advantages for mounting red dot sights on Glock pistols. The MOS system offers broad compatibility and an easier initial setup, utilizing adapter plates to accommodate a wider range of optics. Conversely, the RMR footprint provides superior stability, a potentially lower profile, and a more direct, durable mounting solution, typically through a direct mount to the slide.
The “best” choice ultimately depends on your individual needs, budget, shooting style, and the importance you place on factors such as optic choice, ease of installation, and long-term reliability. Consider your intended use, technical capabilities, and the long-term implications of your decision.
Further research is encouraged to solidify your decision. Examine a broad variety of options, read reviews, and if possible, handle pistols equipped with both systems to experience the differences firsthand. Careful research and evaluation will ensure that you select the mounting solution that aligns with your shooting needs and preferences.
