Ai Key Slot Rail
M-LOK, standing for Modular Lock, is a free licensed firearm rail interface system developed and patented by Magpul Industries. M-LOK allows for direct accessory attachment onto the 'negative space' (hollow slot) mounting points, and is a competing standard to VLTOR's open sourced KeyMod system for replacing the ubiquitous Picatinny rail in some applications. GOTICAL- 4 Products Combo KeyMod 45 Degree Offset Picatinny Rail Mount with KeyMod Modular, 7 Slots Key mod Rail and 5 Slots Aluminum Key mod Rail 5.0 out of 5 stars 2 $25.95 $ 25.
Remember Betamax? It was the early rival to the VHS videotape format, and at one time, just as popular. But if you were born after about 1980, there’s a good chance you’ve never even seen a Betamax tape.
We’re about to see a similar showdown play out in the world of rifle accessory rails. The picatinny accessory rail system has been the standard for bolting stuff to our AR-15s and other rifles for several years now. It’s an excellent system, especially for mounting optics, but including picatinny rails on a rifle’s foreend/handguard can add a lot of unwanted bulk and weight.
To alleviate this, there are low profile handguards that allow the user to attach small sections of rail only where they are needed. Not a bad solution, but what if we could eliminate the middle step and attach accessories directly to the handguard without the need for a picatinny adapter? The KeyMod and M-Lok systems do just that.
The KeyMod System
Released in 2012, KeyMod was developed and released through a partnership between VLTOR and Noveske. It’s an open-source, public domain design, meaning that any company can make rails or accessories using the system without paying a dime in royalties.
Ai Key Slot Rail Bolt
Handguards built with the Keymod system can be incredibly lightweight, and allow for the direct attachment of any Keymod-compatible accessories. Several companies already produce Keymod rifles and handguards as well as attachments like vertical foregrips, bipod adapters, sling adapters, and flashlight mounts.
Keymod rails consist of rows of “keyholes”. To attach a keymod-compatible accessory, line up the lugs on the accessory with the round part of the keyhole. Slide it forward, and then tighten the screws.
Demo: Attaching a bipod mount to a Bravo Company KMR-13 KeyMod rail
The Magpul M-Lok System
Pretty cool idea, right? Well, Magpul thought so, too. They looked into making some Keymod-compatible accessories, but weren’t happy with the way the system worked with polymer attachments. So earlier this year, Magpul came up with their own competing standard called the M-Lok system. To increase their chances of this new standard taking off, Magpul has also made M-Lok free for other companies to use.
Ai Key Slot Rails
Magpul’s new M-Lok system uses slots in place of the keyholes. The attachment lugs on M-Lok accessories are t-shaped and bi-directional so they can be placed at the front or rear of the slots.
Demo: Attaching a flashlight mount to a Midwest Industries M-Lok rail
Ai Key Slot Rail Bracket
So now we’ve got two open-source direct-attachment rail system standards that are a little different but ultimately seek to address the same problem. Will the marketplace tolerate two standards? Or will one eventually dominate, leaving the other to become the forgotten Betamax of the AR world?