Modular rail systems such as M-LOK and KeyMod offer a high degree of flexibility when mounting accessories to firearms, but is one better than the other?

Magpul’s M-LOK technology is currently en vogue with enthusiasts and professionals alike. On the other hand, KeyMod (developed by VLTOR) has persisted somewhat in spite of dwindling interest in the platform over the last several years. 

KeyMod: First In, First Out

When KeyMod was first introduced, it was touted as the replacement for the standard M1913 Picatinny rail and completely disrupted the firearms accessories space. There wasn’t anything else like it on the market - at least, not yet. 

The system derived its name from the distinctive keyhole-shaped slots that, when combined with a KeyMod nut, allowed accessories to be quickly mounted along the handguard. Shooters could now utilize lights, lasers, and foregrips in any position and at any angle.

Bravo Company 15" KeyMod Handguard for AR-15 rifles

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While KeyMod enjoyed immense popularity for several years, being first to market hasn’t granted the system unlimited staying power. The more secure, more versatile M-LOK system from Magpul has inarguably eclipsed KeyMod as the new standard. 

M-LOK (The M Stands For Modular)

Magpul first introduced the M-LOK system to address the shortcomings of KeyMod. It offers greater comfort and modularity while bridging the gap between the M1913 Picatinny rail and the KeyMod system, resulting in supreme reliability. 

Slots in the handguard serve as “negative space mounting point[s]” for hard mounting accessories. The attachment is secured through these slots, so there is no need for the addition of external rails - making for an all-around sleeker profile. 

Moreover, M-LOK-compatible accessories are plentiful which gives shooters a wider range of choice when selecting attachments for their firearm. 

Magpul's M-LOK Handguard

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Greater Versatility Without Compromise

M-LOK slots are also more versatile, offering a greater range of positions to secure attachments to the firearm. The handguards themselves are lightweight as they use less material, yet were shown to be more durable than KeyMod during drop tests. 

Lights and lasers can be secured at any angle without the use of special mounts (something that is harder to achieve with either Picatinny or KeyMod systems.) The user gains a lot of flexibility without giving up anything significant in terms of functionality or performance. 

And The Winner Is…

Magpul’s M-LOK system is by far the most popular, so much so that people who are new to firearms may not even be familiar with the KeyMod system. It just wasn’t as successful despite kicking off the trend of modular rail systems back in 2012. 

While KeyMod hasn’t completely died out it has become a lot more niche. By contrast, browse online or visit any gun store and most firearms will come equipped with a top-mounted Picatinny rail and an M-LOK handguard from the factory. Accessories are readily available.

Radical Firearms AR-15 with M-LOK handguard and MFT Stock

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The proof is in the pudding. Based on market share it is clear that the people have spoken and consider M-LOK to be decisively better than KeyMod. However, it could only be a matter of time before a new modular rail system comes along and replaces M-LOK as the newest of new standards.