A Brief History of the M-LOK vs. KeyMod Debate for AR Accessories

Magpul industries released a modular system in 2009 called MOE, but they were noodling with the concept in 2007. The idea was to get rid of the sharp picatinny rails for applications where hand-guards would be used to mount multiple accessories at varying angles. The standard quad rails aren’t comfortable to hold, but they work. Magpul wanted to make them better.

In 2012, KeyMod was released as a newer (and in some ways better) way to do the same thing. They released patent information to makers, so that the majority of manufacturers could provide third-party accessories for their rails. KeyMod surged in popularity over clunky MOE rails.

The first major advantage was that you could get free floated barrel guards from major manufacturers. You also didn’t have to mess around with stripping the guard every time you wanted to change something, because there weren’t any loose nuts. You can attach and detach rails and other accessories with ease, anywhere they are needed, and without sharp picatinny edges poking into your hand at the range, or clunky covers to place over them.

Magpul took issue with the KeyMod system, the most touted reason being that it didn’t play nice with polymer accessories from Magpul. They may have been a little butt-hurt about the popularity that VLTOR received too, but that’s speculation. Their answer was the M-LOK system, which did essentially the same thing as KeyMod, but instead of using key-slots and angled nuts, a t-nut system provides a more direct surface contact that isn’t angled. They also made the new system open-source to open the door for more manufacturers, as VLTOR did with KeyMod.

Shooters have gone back and forth over which is better, KeyMod or M-LOK. MOE has been lost in obscurity. Arguments are made over looks, repeatability, reliability, the potential for slippage that could adjust point-of-aim if the rifle is dropped, and all manner of other tests to fight about. That debate was ended recently when the DoD approved testing of the two systems to see which would be the best for American SOCOM forces. Their decision here.