MLOK

M-LOK is a firearm accessory mounting system developed by Magpul Industries. It uses a pattern of rectangular, slot-like openings along a firearm’s handguard, forend, or receiver to accept modular attachments. Introduced in the early 2010s, M-LOK was designed to provide a lightweight, versatile alternative to traditional rail systems and has been widely adopted on a variety of platforms, especially AR-15 and other modular firearms.

The mounting mechanism relies on hardware that slides into the M-LOK slots from the outside of the handguard. A nut insert or captive nut resides inside the slot’s hollow cavity, and a screw or bolt is tightened through the accessory into that insert. As the fastener is tightened, the accessory is drawn firmly against the surface, creating a secure attachment without the need for a continuous rail along the entire length of the handguard.

Compatibility and use notes distinguish M-LOK from other systems. M-LOK slots are not inherently compatible with KeyMod slots, which use a different mounting geometry. Accessories must be specifically designed for M-LOK to ensure proper fit and load transfer. While M-LOK is commonly installed directly on handguards and receivers that incorporate the pattern, some arrangements allow mounting to Picatinny rails with adapters, though the standard use is on surfaces with M-LOK slots.

Advantages of M-LOK include reduced weight, simpler manufacturing, and modular attachment options. It has become a common standard across many manufacturers and platforms, reflecting its balance of strength, ease of use, and cost. See also KeyMod for an alternative lightweight mounting system.