MLOK is better. We can say it with conviction now that NSWC-Crane has released a slideshow that details the processes they used to conduct the testing and the results of said testing.
With no appreciable difference in cost to the consumer and MLOK being theoretically cheaper to produce, there is literally no reason for KeyMod to continue to be offered by top-tier manufacturers. Sure the open source nature of KeyMod is attractive, but getting the OK to build MLOK parts isn’t tough, and the benefits to the consumer appear to be well worth it.
I should come clean as an MLOK fanboy, in past reviews I have said “I really wish that it came in MLOK” when reviewing firearms or accessories. I have long felt MLOK is better and when you are spending your hard earned dollars on quality rails, making the right choice with your dollar matters. Now with the new information from Crane, we can make the right call on that next rifle build relying on science instead of industry rumor and feels.
Crane installed 18 rails to upper receiver groups to conduct the testing from three different manufacturers, three keymod and three MLOK in each style. The full details of the test can be found by reading the slides in the following PDF.
Some of the most interesting data points in the test come out of the repeatability testing. This is where they mounted a bit of rail to either KeyMod or MLOK, then mounted a laser to that rail. The laser was then zeroed then removed without removing the laser from the rail section, and a POI shift was recorded.
KeyMod showed a 0.2 MOA to 14.6 MOA shift, MLOK on the other hand only exhibited a 0.0 MOA to 6.6 MOA shift. The most impressive of this bunch was two Seekings MLOK rails that showed an average POI shift of only 0.1 and 0.2 MOA.
There are a few areas where KeyMod and MLOK came out about equal, but again, the results aren’t enough for me to even consider KeyMod for any use. It may be just fine if you already have KeyMod on a rifle, but given a choice between the two, the data suggests that you should choose MLOK.
If that isn’t enough to sway you, maybe the drop test is the data point that you needed to see. Lord knows I have knocked my rifle off a table or my tailgate a time or two, drop resistance is something I really need to consider like most of you.
With only a third of the KeyMod rails retaining the accessory and the damage to the rail being rather extensive, it is hard to not take this into account when buying a new rail. MLOK, on the other hand, retained all of the mounted accessories with some slight damage indicating rearward movement of the mount.
The only way that KeyMod was described as being easier to use was attaching an accessory onto the rail. They said that more care was needed to ensure that the mount was attached properly with MLOK and the nature of KeyMod allowed a user to be less precise and still get the accessory mounted properly.
The conclusions that Crane came to are enough to make me no longer take KeyMod seriously. I might not be a hard user, but if it costs the same money as MLOK, there is no reason to go KeyMod. You can head over to Soldier Systems to read more about the testing or just download the PDF above and make your own conclusions. I highly recommend reading through the slides and making your own decision. Like I said previously, it is really hard to justify buying more KeyMod after seeing hard results like this, MLOK is better in just about every way.
Disclamer: this post was written under the influence of heavy cold medication. Even if it is unintelligible, MLOK is better.