The Complete Guide to the M-LOK Attachment System

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8 minute read

Confused by those M-LOK slots on your new firearm? You’re not alone! With M-LOK appearing on nearly every modern sporting gun these days, mastering this attachment system is key to customizing your firearm to perfection.

Buckle up as we dive deep into the world of M-LOK, exploring its history, functionality, and why it’s become the go-to choice for shooters everywhere. Most importantly, we’ll demystify how to use those M-LOK slots! Ready to unlock the secrets of M-LOK? Let’s kick things off with the question on everyone’s mind!

What is M-LOK?

M-LOK, short for Modular Lock, is an attachment system for firearm accessories. Released by Magpul Industries in 2014, M-LOK has quickly become one of the most popular mounting solutions in the firearms industry. But what makes it so special?

The Complete Guide to the M-LOK Attachment System

Imagine your rifle’s handguard as a blank canvas. M-LOK provides the “paint” – a standardized pattern of slots that allows you to easily attach various accessories like lights, lasers, foregrips, and more. It’s like LEGO for grown-ups, but way cooler!

The Complete Guide to the M-LOK Attachment System

The Birth of M-LOK: A Brief History

Before M-LOK, we had age-old systems like Picatinny rails and the newfangled KeyMod. While effective, these older systems had their drawbacks. Picatinny rails were heavy and could turn your sleek rifle into a cheese grater for your hands. KeyMod, while lighter, had some issues with durability and consistent mounting.

The Complete Guide to the M-LOK Attachment System

Enter Magpul, that lovable polymer pumping company behind many popular firearm accessories. They saw room for improvement and developed M-LOK as an open-source system. This means any manufacturer can produce M-LOK compatible products without paying royalties, leading to a wide variety of available accessories.

The Complete Guide to the M-LOK Attachment System

How Does M-LOK Work?

Now, let’s get into the nitty-gritty of how M-LOK actually works. The system uses a series of rectangular slots in the handguard or on some parts like a precision buttstock. These slots are typically around 7mm wide and 32mm long although since the design is open source this can fluctuate from manufacturer to manufacturer.

The Complete Guide to the M-LOK Attachment System

To mount an accessory, you’ll use special rectangle-shaped M-LOK nuts that fit into these slots. When you tighten the mounting screws, these nuts rotate 90 degrees, creating a secure lock against the back of the slot. It’s like a mechanical game of Tetris, ensuring your accessories stay put even under heavy use.

M-LOK Screw Close Up

Types of M-LOK Accessories

The beauty of M-LOK lies in its versatility. Here’s a quick rundown of some popular M-LOK accessories:

  • Front Grips: Vertical and angled grips provide improved weapon control and ergonomics. Vertical grips offer a solid hold for close-quarters situations, while angled grips promote a more natural wrist position for extended use. Many handstops also serve as index points, helping shooters quickly and consistently position their support hand.
The Complete Guide to the M-LOK Attachment System
  • Lights and Lasers: Essential for low-light situations and rapid target acquisition, these accessories can mean the difference between identifying a threat or not. Modern weapon lights often feature multiple brightness settings and strobe functions, while lasers can significantly speed up target acquisition, especially when using night vision devices.
The Complete Guide to the M-LOK Attachment System
  • Bipods: These attachments steady your aim for long-range shooting, dramatically improving accuracy at distance. Many M-LOK bipods are adjustable for height and cant, allowing shooters to adapt to various shooting positions and uneven terrain.
The Complete Guide to the M-LOK Attachment System
  • Sling Mounts: These allow you to attach your sling securely, providing a crucial connection point between you and your firearm. M-LOK sling mounts often feature quick-detach (QD) functionality, allowing for rapid attachment and detachment of slings.
The Complete Guide to the M-LOK Attachment System
  • Rail Sections: These add Picatinny rail where needed, bridging the gap between M-LOK and older accessory systems. Rail sections allow you to mount accessories designed for Picatinny rails onto your M-LOK handguard, offering backward compatibility with a wide range of gear.
The Complete Guide to the M-LOK Attachment System

And that’s just scratching the surface! The M-LOK ecosystem is vast and continually growing.

Mounting M-LOK Accessories: A Step-by-Step Guide

Ready to mount your M-LOK accessory? Here’s a simple 7 step guide:

1. Identify the M-LOK slots on your handguard

2. Make sure the M-LOK nuts are on the screws.

3. Position your accessory over the desired slots

4. Insert the M-LOK nuts into the slots

5. Begin tightening the mounting screws

6. As you tighten, the nuts will rotate to lock in place

7. Fully tighten the screws to the manufacturer’s specifications

Note: The nuts may need to be screwed on more in order to catch when being installed.

M-LOK vs. KeyMod: The Great Debate

In the world of modular attachment systems, M-LOK’s main competitor is/was KeyMod. While both systems aim to provide a lightweight, modular solution, M-LOK has gained a significant edge in recent years.

Handstop or Baracade Brace on an AR15 Handguard

A 2017 US SOCOM study found that M-LOK outperformed KeyMod in drop tests and rough handling scenarios. This led to many manufacturers and users switching to M-LOK, solidifying its position as the preferred system for many shooters.

KeyMod has basically died out. It is still around but it is seldom found on new products.

Conclusion: Unlocking the Potential of M-LOK

M-LOK has revolutionized the way we customize our firearms. Its lightweight design, versatility, and growing ecosystem of accessories make it an excellent choice for both casual shooters and professionals alike.

The Complete Guide to the M-LOK Attachment System

Whether you’re building your first AR15 or upgrading your current setup, understanding M-LOK opens up a world of possibilities. So go ahead, experiment with different accessories, and find the perfect setup that works for you. After all, that’s what M-LOK is all about – making your firearm truly yours. Happy customizing!

FAQs About M-LOK

Let’s address some common questions about M-LOK:

Is M-LOK proprietary?

No, M-LOK is an open-source system that any manufacturer can use.

What tools do I need for M-LOK installation?

Typically, you’ll need an Allen wrench or Torx driver, depending on the specific accessory.

Can I add M-LOK slots to a non-M-LOK handguard?

While possible, it’s not recommended unless you have professional machining skills. It’s much better, cheaper, and less time-consuming to replace the handguard with an M-LOK compatible one.

How durable are M-LOK mounts?

Very durable! M-LOK has been proven to withstand significant stress and impact in military testing.

One Last Tip

If there’s anyone that knows the AR-15 platform, it’s the US military. As a special offer for our readers, you can get the Official US Army Manual for AR-15/M4/M16 right now – for free. Click here to snag a copy.

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