M-LOK vs KeyMod – 2021 Comparison

| Last Updated: May 11, 2021

Trying to decide whether to buy a new AR-15 with an M-LOK rail system or a KeyMod rail system?

Well, you've come to the right place.

In the article below, we will cover what the similarities and differences are and what advantages each brand has over the other. We hope all your questions are answered in this riveting read.

Photo credit: guns.com

M-LOK vs KeyMod

M-LOK

KeyMod

Pros

Pros

Wide online availability

Been around longer

Performs better under drop test

More readily available on the market

Developed by Magpul, a trusted weapon accessory producer

Open design domain allows other manufacturers to produce this product without paying royalties

Cons

Cons

Not great market penetration yet due to being newly available

Doesn’t perform well under the drop test

Greater variation of module attachment causes different alignment issues

Parts are smaller and so may easily be lost

Best For

Best For

Use with polymer accessories

Metal accessories

How Does M-LOK Work?

The M-LOK or Modular Lock is produced by Magpul Industries and became available for purchase in 2014. The M-LOK provides the ability to attach an accessory or accessories to a weapon. 

Derived from the Picatinny rail system, it offers a more sleek design, reducing the bulkiness and weight that many complain about with the Picatinny systems. 

The M-LOK uses a rectangle T-nut that fits into a rectangle slot on the M-LOK rail. With a twist of a nut, the M-LOK attachment receiver is in place and ready to receive the weapon module you wish to add. 

Step-by-Step

First, arrange the rectangle T-Nuts so that they're aligned in such a manner they'll sit in the M-LOK slots. You'll know the attachment is properly seated when the base of the accessory is flush with the M-LOK rail system.

Next, you'll need a hexed wrench to rotate the T-Nut until it's in the locked position. The locked position is achieved when the nut is rotated 90 degrees.

Lastly, continue to tighten the screw until the proper tightness has been achieved.

  • For a metal to metal attachment, 35 inch/lbs. should be achieved

  • For polymer to metal or polymer to polymer attachments, 15 inches/lbs. should be achieved

Photo credit: gunpros.com

How Do KeyMods Work?

Developed in concert with VLTOR Weapon Systems and Noveske Rifleworks, the KeyMod handguard was designed to offer an alternative to the Picatinny rail system. KeyMod was released to the public in 2012, hoping to standardize the universal attachment systems. 

Instead of using a Picatinny style rail, the KeyMod is designed to allow a gun owner to attach a module directly to the rail. The capability to mount directly onto the KeyMod rail also allows for Picatinny rails to be attached.

The KeyMod world is much like the M-LOK system in that a locking bolt is inserted into a hole then tightened into place. In this case, the holding nuts are round with a flare at the end, and they fit into keyhole-shaped slots on the rail. Hence, they get the name KeyMod.

Step-by-Step

First, align the KeyMod nut the proper way. There’s a backer nut, which is the portion that fits into the KeyMod slot, that has a protrusion on a single side only at the base. This extended portion should point in the direction of the weapon's muzzle.

After placing the backer nut into the large part of the KeyMod slot, slide the module as far forward, toward the muzzle, as possible.

Screw the attachment in to hold the module firmly in place. 

Photo credit: luckygunner.com

Relevant Characteristics Between M-LOK and KeyMod

M-LOK

Characteristics

KeyMod

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Enter your text here...

Photo credit: tactical-life.com

No Difference

Weight Benefits

No Difference

During drop tests, the M-Lock accessories performed better at staying in place

Attachment Security

During drop tests, the KeyMod had attachment separation issues

About the same, the locking mechanism on both are straightforward designs

Ease of Use

About the same, the locking mechanism on both are straightforward designs

Similarities and Differences

While these two rail systems are similar in many ways, they have subtle but distinct differences. Here we're going to examine the similarities and differences so that you can better determine which is better suited for your needs. 

M-LOK and KeyMod Differences

Most importantly are the differences, so we’re going to take a look at those first. As mentioned above, the key difference in performance was seen during the drop test. The M-LOK outperformed the KeyMod in this test repeatedly. 

Failing at the drop test might seem like an insignificant matter because a person is supposed to maintain positive control of a weapon at all times. However, accidents happen, and if you drop your weapon at night and the tactical light comes off, it's going to be difficult to relocate. 

Another place these two differ is in reports of when parts do come off or when changing attachments, and the KeyMod parts are smaller and more difficult to find. Basically, it's not recommended to perform module maintenance in the field at night. 

The M-LOK is less expensive to produce because M-LOK is a Magpul product; approved Magpul vendors can only produce them. In contrast, KeyMod is an open domain design and allows any company to manufacture KeyMod components without having to pay royalties to the king. 

Because of open domain KeyMod offers, there are significantly better improvements made more frequently than with M-LOK.

Photo credit: blog.mountsplus.com

Another difference between the two is how the modules attach. The keyhole feature of the KeyMod keeps the modules in place better while being used under normal conditions, meaning not purposely being dropped.  

While the M-LOK rectangular bolt and rectangular slot allow a little play as to where the modules are placed in the slot.

Many of these differences are minimal and can be easily overlooked based on shooter preference. Some swear by the Magpul brand and so naturally lean toward anything they produce. While others think that because KeyMod was the first to challenge Picatinny and left their design domain open, they hold the candle in the better trusted.

M-LOK and KeyMod Similarities

These two weapon modification kits are similar in many ways. They were both designed to move away from the bulk and weight of the Picatinny rail system. Also, they both offer a larger array of modules that can be attached to the desired weapon. 

They're equally as light as their counterpart, and both have straightforward attaching mechanisms that make for easy installation of your desired load-out. 

The M-LOK and KeyMod are great alternatives to the Picatinny rail systems. They both hold up well under normal operating environments and allow the shooter to pick and choose where they want their modules; all of this without unnecessary width in other areas of the weapon. 

They’re both priced relatively well and can fit into almost anyone's budget. They can both be found in most places where aftermarket weapon parts are sold. 

Whether or not a person chooses M-LOK or KeyMod really comes down to personal preference. Perhaps the keyhole style locking mechanism is better for you, or maybe the fact that Magpul makes M-LOK matches other gear on your weapon. 

Either way, both of these weapons are going to perform the task they're asked to perform, allowing you, the shooter, to attach all the gadgets and gizmos you desire to customize your weapon. 

So, when you're shopping for your next rail system, you know some of the characteristics that both KeyMod and M-LOK share, and you can focus more on the differences.

Photo credit: guns-review.com

Advantages of M-LOK Systems

There are a few advantages that set M-LOK apart from KeyMod rail systems. For starters, the M-LOK by Magpul, according to some, offers a better look than the KeyMod. 

We know this has nothing to do with performance, but hey, no one says a weapon's component has to be functional or stylish. In most people's opinion, M-LOK seems to be the winner as far as looks are concerned.

Also, because Magpul makes M-LOK, it has better capabilities in the plastic handguard department, making it easier to manufacture in a multitude of variations. Also, because Magpul makes the M-LOK, it has a company that's already well funded, giving it a clear advantage in creating more attachments and modules for multiple weapon systems. 

Another advantage is when the M-LOK was compared to the KeyMod in a shot test where modules were attached with a point of aim identified, then removed and reinstalled, the M-LOK maintained its point of aim without having to re-zero. 

The ability to remove a laser or optic and reattach it without having to re-zero can be a huge deal for some. If you wanted to remove a laser for some reason and replace it with a tactical flashlight, you could easily do so.

Let's say you change out your laser for that flashlight and decide it was a horrible idea and want to put the laser back on. Again no problem, your laser should still have the same aim when it was removed.

In comparison, when the same test was performed on KeyMod rail systems, the aim point shifted and the laser or optic had to be recalibrated. So, in this scenario, M-LOK wins. 

Photo credit: targetbarn.com

In Summary

To many weapon owners, the M-LOK is a better-looking rail system. The M-LOK rail system offers greater capabilities in plastic handguards also. 

Compared to the KeyMods, the M-LOK performed better at maintaining the point of aim when a laser was removed and reattached to the weapon with nearly zero shift. 

If you like to remove your gadgets and interchange them with others, then the M-LOK rail system might be the right choice for you. 

Advantages of KeyMod Systems

The biggest advantage of KeyMod over M-LOK is its availability. Because KeyMod made it so any manufacturer can use their design without paying royalties, KeyMod is readily available with a multitude of attachments. 

Because they were the first to step up and challenge Picatinny, many weapon enthusiasts swear that KeyMod is the best by default. Also, being the first gives it an edge on M-LOK by having more time to secure an abundance of available stock. In contrast, M-LOK is still trying to establish itself.   

KeyMod's keyhole style locking also makes some feel it has better locking mechanisms than M-LOK because these modules can only fit one way. Because the mechanism's style has to be fitted in facing a certain direction and slid into place then tightened down, many users of KeyMod swear the reliability of KeyMod is superior to M-LOK. 

Photo credit: thefirearmblog.com

The way the KeyMod is designed also prevents the user from installing an attachment backward as the bolts will only allow a component to be attached one way. This is vital to someone new to the weapon attachment world who may be unsure as to how their modules are supposed to line up with the weapon.

While many shooters feel M-LOK is the better looking of the two, many still argue that KeyMod's keyhole feature adds texture to the blank space in between components. While we understand that looks are the least important of attributes on a weapon system, we also understand everyone likes to have their personality reflected in the things they own.

With looks in mind, we thought it wise to compare the two in this manner, allowing the reader to decide which is more appealing to them.

In Summary

There’s no question that KeyMod has been produced longer than M-LOK, and so has more of a lifespan to prove their worthiness. To many, this fact makes them better than M-LOK. 

Also, because they’ve been in production longer, many weapons are already fitted with KeyMod rail systems, and changing them out might feel like a waste of money. It all boils down to user preference. 

If there's something that catches your eye about KeyMod over M-LOK, there aren't enough critical differences between the two to scream not to buy them. 

What About Picatinny Attachments?

Picatinny rail attachments are the leader in rail attachments, even with other lighter versions on the market today. Picatinny rail systems were designed in the 1980s and are the rail systems used by the United States Military on all of their weapon systems. 

Many civilians complain about their bulkiness and added weight, but when we asked some infantrymen from the U.S. Army Infantry, they looked at us with confusion and asked what weight. 

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The soldiers of the infantry said after everything else they have to carry, the ounces produced by the Picatinny rail system go unnoticed. 

Some did mention that when heat shields were applied to all four sides of the rail system, soldiers with smaller hands did have trouble holding the forestock of the weapon, but that was easily navigated by attaching a pistol grip to the forestock to accommodate.

The Picatinny rail system is rugged and durable. 

So well proven on the battlefields that many think going with anything else is foolish. With such a proven record of survivability and durability, if you know your weapon will take a beating, then Picatinny might be the better choice. 

Some complain that the design of Picatinny is similar to a cheese grater and is abrasive to the hand. Soldiers said that's why they wear gloves while conducting maneuvers or on the battlefield to protect the hands from discomfort. 

However, like M-LOK and KeyMod, choosing Picatinny is all based on the user's preference. Many shooters want to mimic the military as closely as possible, so choose the Picatinny. 

Picatinny rail systems have been on the market for decades, making them one of the most trusted names in rail systems currently.

What About Weaver Attachments?

Weaver weapon rail attachments are a variation of rail systems made to attach different modules to the weapon. They work much like the Picatinny rail system, as attachments can be placed in various locations along the length of the weapon. 

It's important to know that weaver modules will fit Picatinny rail systems. In contrast, the Picatinny attachments won't fit Weaver rail systems. 

Neither rails systems will affect the effectiveness of a long or short action rifle. What attachments a shooter chooses for their weapon system is purely based on preference.

While Weaver is popular amongst many shooters, the Picatinny rail system is more popular because of its use in the United States military.  

Photo credit: americanfirearms.org

While Picatinny rail systems won't fit Weaver systems, the difference in size is minimal. Someone proficient with a file or Dremel tool might be able to file down where the modules attach to the rail system. Obviously, this isn't an ideal situation, but sometimes such measures might need to be taken. 

Rail systems, in general, are a great addition to a weapon because they allow for the quick addition of desired modules like scopes, flashlights, or lasers. Another great module to consider for your weapon, especially for those long-range shots, is a bipod. 

A bipod attachment is good because it gives the weapon a sound platform to fire from. Some bipods offer adjustable leg lengths allowing the shooter to adjust for uneven terrain.

Weaver has been producing rifle optics for decades, and so their scopes are often sought after. Before purchasing a Weaver attachment, it might be wise to determine if you have Picatinny rails or Weaver rails to avoid fitment issues.

Bottom Line

To sum all the information above up, what rail system you choose has more to do with shooter preference than anything else. There simply aren't enough critical differences to hinder a weapon owner from going with any of the models they choose. 

If, as a shooter, you think the KeyMod looks better, that's as good a reason as any to choose them. If you feel that M-LOK is better because Magpul produces them, that's a solid reason as well. 

When choosing a rail system, ask yourself what you're looking for from the rail system as far as performance, then choose a rail system that fits that criteria. Chances are they'll all meet your standards and will be decided on by the smallest of details. 

Photo credit: badassoptic.com

People Also Ask

No matter how hard we try to tie everything up in a nice little bow, there are always a few follow-up questions we somehow didn't cover. We have done our best to select the most common questions we get asked and included them below. We hope your question is among them and we were able to answer it adequately. 

Does Magpul Make KeyMod Accessories?

The short answer is no. Because M-LOK and KeyMod are essentially competitors selling the same thing by a different variant, it wouldn't make much sense for Magpul to produce the competition's product. 

Are Gun Rails Universal?

As far as gun rails being universal, it depends on what you're referring to. If you're referring to whether they can all be installed to an AR platform weapon, then yes. But if you mean can KeyMod attachments be placed on M-LOK rail systems, then no. 

The reason is in the design of the individual rail systems and how they're designed specifically to fit their attachments.



Josh Lewis the managing editor at Gun Mann and when he isn't writing about guns he is more than likely tinkering with them. He also enjoys hunting, fishing and spending time outdoors. As a lifelong gun owner he knows his stuff!