AR Handguards: KeyMod vs. MLOK

If you want to upgrade your rifle with more modern furniture, but don’t want quad rails or traditional handguards, you have two choices: M-LOK or KeyMod. Is one better than the other in general? What are the best handguard models for each style? What are the best models of handguards for each style?MLOK (left), vs. KeyMod. Both styles of handguards offer more attachment points for accessories. They also often have another advantage: they are free-floating. The M-LOK handguards and KeyMod models that attach to the barrel nut, rather than the barrel, improve the mechanical accuracy of a rifle. It is in contrast to traditional handguards which attach to the barrel. This means that the force imparted to the handguard will transfer to the barrel affecting the point of impact. Free-floating is the most popular and widely available style of handguard, but not all MLOK or KeyMod models are free-floating. Some of the cheaper and simpler handguards with these attachment systems still use the traditional method. Both rail systems began in the private sector and were eventually adopted by armed forces around the world. KeyMod, designed by VLTOR Weapon Systems and released by Noveske Rifleworks as an open-source project in 2012, was originally developed by VLTOR Weapon Systems. The name is derived from the unique keyhole-shaped slots in the design. M-LOK (Modular Lock), invented by Magpul, was released as the MOE handguard design in 2007. Original Magpul MOE handguard. The original MOE system had a series slots (similar to M-LOK), but the user was required to install a T nut behind the handguard. This meant that you had to remove the handguard every time you wanted something mounted or find a way of dropping it into place. Magpul realized the limitations and released a revised system in 2014. This is what we now know as MLOK. M-LOK, which is owned by Magpul, allows other companies to use the design as a “conditional license” and not a true open-source. The mounting systems are what make both rail systems so effective. KeyMod (top) and M-LOK. Photos: Crane. For KeyMod, the attachment consists of a flared screw that slides into the large hole and then into the small hole. The user tightens the bolt and attaches whatever accessory they are trying to install. KeyMod accessories are usually inserted into at least two holes to ensure the best attachment. M-LOK uses rectangular slots. Attachments are secured with T-nuts which are rotated perpendicularly to the slot and then tightened. KeyMod is more intuitive and user-friendly, but not by much. M-LOK is used by the U.S. Military when they want to use something other than Picatinny Rails. USSOCOM chose it after testing by the Crane Division at the Naval Surface Warfare Center showed it to be superior in some ways. The Geissele Super HK Rail and Geissele Super Modular Rail were selected by different groups within the U.S. Military. Of course, the new Sig Sauer M5 uses an M-LOK as well. Crane tested three different handguards with M-LOK slots and KeyMod slots, from Aero Precision Midwest Industries and Seekins Precision. Stress testing revealed that KeyMod handguards were the most fragile. While no handguards failed when recoiled, KeyMod was found to be the most fragile. The mounting bolt will usually crack the handguard. In drop tests, several handguards were also freed from the barrel nut. Crane’s KeyMod vs. M-LOK comparison study. Photos: Crane.Part of testing included zeroing a IR laser. The unit was removed from the handguard and then reinstalled. POA (Point of Aim shift) was checked to determine which mounting system would hold zero better. M-LOK was the clear winner. So, what does this mean in terms of pros and cons? The average user won’t be able to tell the difference. Most people don’t drop their rifles repeatedly on concrete or use an IR laser aiming system. Crane’s tests revealed that KeyMod failed only when it was subjected abuse far beyond the abuse that a typical civilian owner would ever subject his rifle to. The availability of compatible accessories is the biggest drawback for the current year. M-LOK is the most popular mounting option, so today’s accessories are primarily offered with M-LOK and Picatinny mounting equipment. There are also plenty of KeyMod compatible items, but not as many. KeyMod’s popularity in Europe is likely to be a factor in its continued availability. Military testing has shown that KeyMod’s two main shortcomings are its durability and ability to maintain zero with laser aiming systems. M-LOK handguards are the best choice if you want to use your rifle with night-vision and/or make it bomb-proof. Geissele Super Modular Rail MK4 Geissele is one of the first companies that designed an M-LOK Rail with a night vision system in mind (and the need to minimize rail flex so as to preserve zero). The Super Modular Rails can be mounted with a MAWL, PEQ-15 or similar device on the front end of the handguard. Geissele Super Modular Rails have a MSRP between $275 and $350- depending on the length of the rail and the finish chosen. Aero Industries Quantum MLOK Handguards Aero Industries Quantum MLOK handguards offer a great middle-ground M-LOK option. These handguards are durable enough to withstand the abuse that most users will subject them to and can mount accessories securely. They feature a Picatinny Rail on top, M-LOK Slots at 3, 6, 9 o’clock, and QD Slots at the rear. The MSRP is $110 but you can find them for less than $90 if you do some searching. There are different lengths and finishes. Magpul MOE M-LOK Handgaurd Looking to add some M-LOK to a budget-friendly M4 replica? Magpul MOE handguards have been the standard handguard for a long time. These two-piece handguards can be installed on any rifle that has a front sight block and a D ring (circular or triangle handguard caps work). They are functional, durable, and inexpensive. These are not free-floating, but they are simple and cheap. They are available for carbine-length, mid-length, and rifle-length systems and feature MLOK slots at 3, 6, and 9 o’clock. Choose from black, FDE or grey, and OD green. They are available for less than 40 dollars. Bravo Company KMR Alpha This is a free-floating aluminum handguard that has KeyMod slots at 3, 6 and 9 o’clock. Available in black or FDE, they come in a range of lengths from 7 to 17. Bravo Company is a top manufacturer of AR-pattern weapons and accessories. This is the best KeyMod handguard you can get. The MSRP is different depending on the length. It starts at $180 for 7-inch and 8-inch rails, and goes up to $235 for 17-inch rails. However, you can often find them cheaper at third-party retailers. Leapers Super Slim KeyMod HandguardOnly available in 15-inch and 17-inch lengths (for AR-15 and Ruger Precision rifles, and 17-inch for selected AR-10 variants), the Leapers SuperSlim is an excellent mid-tier option for someone looking for a decent KeyMod handguard that doesn’t break the bank. It has a fully railed top, with KeyMod slots at 3, 6 and 9 o’clock. It also features a slim profile to fit low-profile gas block and built-in anti rotation tabs for securing mounting. The MSRP for these rails is $140. However, they are usually available at third-party retailers for less than $100. Bravo Company PKMR The PKMR is the KeyMod version of Magpul’s MOE Handguard. These are available in FDE and black, and can be used with gas system rifles that have a round end cap or a triangle end cap. The MSRP for these accessories is $40, but they are often found for less than half that price. This makes them a great choice for those who want to add a few accessories to their handguard. The target grids and bullseyes are measured in MOA. Subscribe to the Gun Digest newsletter and we will send you your print-at home target pack immediately. Enter your email below.