M-LOK vs KeyMod Mounting Systems: Differences & How To Mount

When it comes to mounting accessories on your AR-15, there are two popular options: M-LOK and KeyMod. Both systems are based on a slot system rather than the rail system of the Picatinny and Weaver mounts, which means a smoother surface and more mounting options. But what are the differences between M-LOK and KeyMod, and which one is better?

In this article, we take a deep look into these two mounting systems, covering everything from how to mount accessories on both systems to what type of accessories is better for each mounting system.

What Is An M-LOK System (Modular Lock)?

A Modular Lock, or M-LOK system, is a rail interface system developed by Magpul Industries. An M-LOK rail allows for the direct attachment of accessories, creating a cleaner, sleeker look and an improved performance.

What I really like about this rail system is that it uses a T-nut system, which allows you to attach a variety of accessories in different positions for an even more customizable setup.

M-LOK System

What Is A KeyMod System?

Created by VLTOR weapon systems, the KeyMod system also offers a range of accessory options. The name is derived from the keyhole-shaped slots, which resemble classic keyholes. Compared to the M-LOK rails, Keymod rails offer a more effortless and smart mounting system – you simply insert the lugs into these “keyholes” and then slide them into place; it’s as easy as that!

KeyMod System

What Are The Main Differences Between M-LOK vs KeyMod Systems?

Here are the main differences between the Keymod vs M-LOK.

  • Attachment Mechanism: The main difference between these two systems is the attachment mechanism – M-LOK rail systems use T-nuts for secure attachment, while KeyMod uses keyhole slots.
  • Aesthetics: The M-LOK mounting system has a more streamlined appearance, whereas KeyMod slots have a more industrial, mechanical look.
  • Strength: Various tests indicate that M-LOK systems often have a better pull-out strength compared to KeyMod. When we also did some drop testing, it was evident that the M-LOK offered superior durability compared to the Keymod rail.
  • Industry Adoption: M-LOK has been adopted more widely, partially because it is open-source and free to use. Therefore, there are more M-LOK accessories than Keymod accessories available.

M-LOK vs KeyMod

How To Mount Accessories On A M-LOK Handguard

To mount accessories on a M-LOK handguard, follow the below steps.

  1. First, identify the position on the accessory rail of the handguard where you want to mount the accessory.
  2. Next, insert the T-Nut into the rectangular slot on the handguard from the rear side.
  3. Slide the accessory onto the T-Nut and tighten the screws into the T-nuts.

Always ensure your accessory is securely attached and aligned before you do a field test.

How To Mount Accessories On A KeyMod Handguard

To mount Keymod accessories, you need to:

  1. Insert the key-shaped nut into the keyhole-shaped slot on the handguard.
  2. Slide the accessory onto the round part of the key-shaped nut via the accessory’s lugs.
  3. Tighten the screw on the accessory to secure it in place – an Allen wrench is advised.

Which AR-15 Accessories Should Be Mounted On KeyMod Or M-LOK Systems?

When it comes to AR-15 accessories, the sky is the limit. However, that doesn’t mean that one rail system is better for certain accessories than another rail system. For instance, M-LOK is better for mounting heavier accessories, while KeyMod may be better for mounting lighter accessories like a red dot sight.

Ultimately, you can mount grips, bipods, sights, and lights on both systems. But when it comes to optimal performance, the weight and size of each accessory should be considered before buying it for the respective mounting system.

Can You Mount A Red Dot Sight On A KeyMod System?

Yes, you can mount a red dot sight on a KeyMod system. Additionally, if the red dot sight isn’t compatible with the rail system, you can always use adapter rails.

If you’re someone who has vision concerns such as astigmatism, like myself, you’ll be pleased to know that specialized red dot sights for astigmatism are also compatible with KeyMod systems. Just like standard red dot sights, these specialized optics can be securely mounted using the appropriate adapter and screws, offering a better shooting experience for those with vision challenges.

Can You Mount A Magnified Scope On A M-LOK System?

Yes, you can mount a magnified scope on a M-LOK system. However, instead of opting for a magnified hunting scope, I would advise you to choose an AR-15 LPVO scope. These scopes are better for the AR-15 platform, especially the M-LOK system, which prefers lighter accessories.

Can You Mount A Night Vision Scope On A M-LOK System?

Night vision scopes, especially night vision scopes for hog hunting, are perfect for the M-LOK system. The efficient mounting mechanism of the M-LOK makes it ideal for switching between night vision scopes and your normal day scopes.

Are There Upper Receivers That Are Not KeyMod or M-LOK?

Yes, in addition to Keymod and M-LOK AR-15 upper receivers, you also get the Picatinny rail and Weaver system. The type of upper receiver you get should depend on your personal preference, use case, and the type of accessories you want to mount.

Frequently Asked Questions

Can M-LOK and KeyMod mounting systems be used interchangeably?

No, these two mounting systems are not interchangeable. You will need to use accessories compatible with your handguard's mounting system. Alternatively, you can use adapters if available.

Is M-LOK a newer system compared to KeyMod?

Yes, M-LOK was introduced in 2014, whereas KeyMod was developed in 2012.

Which mounting systems are more popular M-LOK and KeyMod?

The M-LOK is more popular, especially in military operations. The fact that the M-LOK has free licensing also helped ensure mass adoption compared to the KeyMod system.

Did M-LOK & KeyMod systems replace Picatinny and Weaver rail systems?

No, not entirely. The Picatinny rail and Weaver systems are still widely used. However, M-LOK and KeyMod systems do offer more versatility. Hence, many people prefer them over the Picatinny and Weaver systems.

The Bottom Line

Whether you prefer the M-LOK or KeyMod, both systems offer a robust, versatile platform for your AR-15. Both systems have their pros and cons, but the M-LOK system is more popular, especially in military use. Your choice will ultimately come down to personal preference and the type of accessories you plan to use. Either way, you’ll be left satisfied as both are strong, reliable rail system options for any AR enthusiast.

About the author

Charles Neser

I'm a life long hunter & gun lover. Currently pursuing my Master's Degree (M.Sc.) in Animal Nutrition at University of the Free State.

Leave a Comment