The VHS vs Betamax metaphor has been brought up on a number of occasions. Same goes for Blu-ray vs HDdvd. We all know who won those epic battles, but it may surprise you to find out why they won.
If memory serves (fact is, a quick google search can confirm) Vltor and Noveske partnered up to develop the keymod rail system. “Why do such a thing?” you ask. The answer is simple; demand. While the 1912 attachment rail system works very well and an entire industry has been developed around creating accessories for it, there has always been one common complaint. Well, three common complaints which are technically four… we’ll get to that in a minute.
After the success and subsequent market shift following the release of the keymod system, magpul (not wanting to be accused of becoming stagnant) developed their M-Lok system. Both Keymod and M-Lok are public license, meaning that anyone can use the specs to develop their own rails and accessories (much like Picatinny’s expired copyright on the 1912 rails). So now back to the why…
#1. The 1912 shreds hands like a cheese grater. Not really a problem for me as my hands are protected by the mystical forces of manhood, some of the fairer shooters in our community, be them male or female, do not like the sharp edges that a 1912 quad rail displays. Solution? Add rail covers, that add weight and bulk.
#2. Weight. Again, not really a problem. Some do pointedly testify that a weight savings of 4 to 8 ounces “REALLY DOES MATTER”, but I just don’t see it. The difference between a 6lb, 8oz rifle and a 7lb rifle is completely negligible, and truthfully unwanted. The heavier the rifle, the better the recoil mitigation. AR-15 recoil…. Ha, just had to laugh a bit at that one. These things really only matter in race guns anyway.
#3. Bulk (and kinda #4ish is that the bulk causes it to snag). This is really the only valid argument that I see, and one that both the Keymod and M-Lok effectively deal with. In fact, it is this exact flaw that allowed me to hang my service rifle from my belt on long marches.
So now the solutions. Keymod and M-Lok are both equally soft on the hands, lightweight, and svelte by comparison to the predecessor. Both have myriad accessories that continue to expand in numbers as we speak… as I type… as you read. Is one better?
No, not really. That being said…
I prefer Keymod. I have both rails and several accessories for each. M-Lok just feels a little gimmicky to me. First, in order to attach anything, the nuts must be oriented correctly to slip through the channels. That is extra time consumed in getting them parallel to within 10 degrees or so. Then you also run the risk of not fully turning them the requisite 90 degrees to fully engage the lugs. You must have the accessory completely flat to the mounting surface so that the lugs do not drag on the rail and tighten without having engaged. Whereas Keymod is very forgiving in how it is oriented. Drop it into its slot, push it forward and tighten. It uses a conical nut that will self-level the accessory as it is tightened. Magpul even sites the conical nut as the reason they developed the M-Lok. Keymod won’t work with their polymer parts because the nut would tear right through the plastic.
So it boils down to loyalty. Are you a Vltor/Noveske kind of guy? Then go Keymod and check this ar-15 upper assembly:
If you are Magpul ‘til the cows come home, check out the M-Lok ar-15 upper assembly over here:
Regardless of which route you take, you will end up with a quality piece of kit with some legendary names behind it. The real important thing is to keep building.
And just FYI, VHS and Blu-ray were just cheaper to manufacture. Betamax and HD-dvd were actually better.