Rail accessory systems are one of the most crucial facets of customizing your gun build. Your rail system determines which accessories and components will fit your firearms. For nearly twenty years, the Picatinny rail reigned supreme, but newer systems like M-LOK and KeyMod are attracting attention by cutting down on weight and the need to use rail covers to avoid rail gripping surfaces, while still allowing for nearly limitless customization.
The Picatinny Rail
The Picatinny rail system was the first of the modern series of rail mounting systems. Developed in the mid-1990s as a standardized version of the Weaver rail system, this system standardized the slotted wide dovetail design of the Weaver rail, with a few minor differences including square bottomed slots vs the Weaver’s rounded slots. This means that old Weaver accessories may fit on Picatinny rails, but Picatinny accessories would require modification to fit a weaver rail.
The biggest change made when the Picatinny rail was developed was making a single mounting system standard and predictable. Picatinny was the first system to feature consistent rail spacing. This made it possible to design accessories that could then be fitted to practically any weapon with rails. Eventually, Picatinny rails were mounted not only on the receiver but all over modern firearms. This sparked many more customization options and also motivated the development of new rail systems.
KeyMod is a rail system released in 2012 as a lightweight alternative to Picatinny rails. This system is also open-source, allowing anyone to produce KeyMod compatible products. The design of KeyMods slots changes the way you mount accessories to your rifle.
Instead of using a dedicated rail, KeyMod uses a series of holes attached to narrow slots. This means the addition of KeyMod actually lightens your handguard while still allowing accessory placement. The nut of the accessory is inserted through the hole, then shifted to the slot, where it can be tightened externally until the component is secure.
This makes it simple to attach and remove accessories without having to need a dedicated rail. If you wish to place a Picatinny accessory on a KeyMod rail, you can easily attach a section of Picatinny rail panel directly to your KeyMod slots. This means you can easily mix and match your components across multiple systems.
The M-LOK rail system was released in 2014. M-LOK stands for Modular Lock and is similar to KeyMod, but uses just slots. This system is not open source, but it is open license. This simply means that a company has to get permission from Magpul Industries, the creators of M-LOK, in order to produce components compatible with this system.
Instead of fitting the nut of your component through a hole like the Keymod rails, M Lok uses a specialized T nut that you insert parallel to the slot and locks in place by tightening. After rotating 90 degrees, the nut fits into the inside of the slot and locks in place so you can continue to tighten without the nut losing its grip. This allows you to easily position and secure your accessories from the outside of the handguard.
M-LOK and KeyMod Compared
One of the biggest advantages of the M-LOK system is the fact that it’s difficult for a component to detach, even in the event of a drop. KeyMod parts might be slightly easier to attach and remove but they can sometimes be forced out of place, especially after experiencing recoil or when dropped. Despite this seeming advantage, KeyMod has been on the market longer. This has given it a distinct advantage as far as how many companies are producing KeyMod compatible parts.
Ultimately which system you should choose comes down to personal preference. Like many overlapping systems, one of these two may eventually win out and dominate the market. For the time being each has its fans and plenty of accessory options, so you really can’t go wrong with whatever system you choose.
Handguards and Covers
Both of these new systems are featured predominantly on the handguards of rifles. Many of the handguards designed with KeyMod and M-LOK systems also include a Picatinny rail on top of the guard. The new mounting systems are on the sides, avoiding the need for rail covers to avoid the sharp edge of Picatinny rails where you grip the guard.
If you want the kind of grip provided by rail covers, there are special KeyMod and M-LOK grip inserts for the rails. These textured inserts can make it more comfortable to handle your rifle with these rail systems, without adding significant weight.
If you are looking to try a new rail system, or find new components for your existing system, check out our inventory of rail accessories. At White Knight Supply, we carry thousands of components so you can always find the perfect parts for your build.