Keymod vs M-LOK handguards. Credit: Wikimedia Commons
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M-LOK vs KeyMod
KeyMod vs M-LOK handguards. Credit: Wikimedia Commons

If you’re looking at putting a handguard on your AR-15 that accessories can be directly attached to, it usually comes down to M-LOK vs keyword handguards. And why not? Both are well-made, and both allow you to attach just about any accessory you’d want to an AR-pattern rifle.

They aren’t lines of products so much as accessory direct attachment mounting system designs that some companies came up with, namely Magpul (M-LOK) and a joint venture (KeyMod) between VLTOR and Noveske. They’re both open-source, public domain meaning that anyone can use these designs. Anyone and their brother can (and does) make a handguard that are M-LOK or KeyMod.

You can buy the handguards themselves, such as the following M-LOK handguard from Midwest Industries:

M-LOK vs KeyMod
Midwest Industries M-LOK handguard, Courtesy Midwest Industries

Or this KeyMod rails handguard, also by Leapers:

M-LOK vs KeyMod
KeyMod handguard by Leapers, Credit:
M-LOK vs KeyMod
Daniel Defense Quad Rail Handguard, Courtesy Brownells

Lots of gun owners prefer these to traditional quad rail. Both M-LOK and KeyMod handguards are lightweight and provide a more comfortable hold on the gun without a cheese grater effect on the support hand.

Additionally, some companies sell uppers or complete guns with M-LOK or KeyMod handguards, such as this DDM4 V7 Pro with an M-LOK handguard from Daniel Defense:

M-LOK vs KeyMod
Daniel Defense rifle with M-LOK handguard. Credit:

Or this barreled upper from Palmetto State Armory with KeyMod handguard:

M-LOK vs KeyMod
PSA complete upper with KeyMod handguard. Credit:

How they work differs from your typical Picatinny rail, though plenty of M-LOK and KeyMod handguards have a Picatinny rail as well. Both systems are designs holes machined into the handguard instead of to said rail. The compatible accessories of your choice is mounted to a bracket that locks into said holes.

Depending on the handguard, you can mount accessories on the sides, bottom or top of the handguard. Why are they better than a rail? Picatinny rails require extra metal and therefore add weight. M-LOK and KeyMod direct attachment systems let you bolt whatever you want directly to the gun. Practical AND tactical!

How said M-LOK or KeyMod accessories mount depends on whether KeyMod vs M-LOK is the system you’re using.

The KeyMod system uses a system of keyholes, similar to one you’d find on a door chain. You have a large hole that the accessory lug goes into, then a smaller track.

Insert, then push and it locks in place. Tighten the lug screw and the accessory bracket is locked down. There might be one, two or three locking lugs depending on the accessory you’re mounting.

M-LOK vs KeyMod
KeyMod adapter by Harris. Note the locking lugs and screws. Credit:

Magpul wanted to do something a little different, as they didn’t quite like how KeyMod performed. So they went to the drawing board and created a different accessory mounting system, the M-LOK. The basic idea is the same (insert mounting bracket, tighten down) but the method is different.

M-LOK vs KeyMod
M-Lok handguard by Magpul. Credit:

The M-LOK rail system uses rectangular holes machined into the handguard. The mounting bracket for your accessories (rail sections, bipod, light, whatever) has locking lugs with bi-directional swivels. They look sort of like a rectangular washer on the bottom of the lug. As you tighten the lug screw, the lug rotates.

M-LOK vs KeyMod
Magpul M-LOK bipod. Note the swivel lugs at the top. Credit:

To insert, you turn the lugs until they’re parallel to the accessory mounting bracket and the mounting holes. You simply drop the bracket in, and then tighten them down. The lugs rotate and tighten, until the lugs are perpendicular to the mounting holes and thus lock the accessory bracket in place.

Some folks might note at this point that USSOCOM – United States Special Operations COMmand, the folks who command the special forces of our military – selected M-LOK for their personnel. So if you’re the sort who is so totally an operator vouchsafing the local Walmart from ISIS and have to have the same gear…that’s what you get.

M-LOK vs KeyMod
via Wikimedia Commons

You look weird wearing a plate carrier in an office, Steve! That kind of vest is not business casual and stop complaining that there aren’t MREs in the breakroom!

But I digress.

For the typical person who wants an accessory mounting system, there are a few reasons to consider KeyMod vs M-LOK and vice versa. Granted, for most folks…it’s not going to make much difference. We get our rifle out at the range, punch some paper and go home. It’s fun!

However, there are a few things to know. The KeyMod rail system is less popular, with fewer KeyMod-compatible accessories being available. Part of the reason why Magpul came up with M-LOK to begin with is they didn’t like how KeyMod worked with accessories on polymer handguards, which the M-LOK system addresses.

Since Magpul is SO HUGE in the AR space, M-LOK has a lot more industry support with hundreds of M-LOK accessories. USSOCOM picking M-LOK as its direct attachment system of choice also makes it a bit more desirable as a group that knows what battle-worthy gear is prefers it. KeyMod fell apart under stress testing, which is something to be aware of.

Again, if you’re the average Joe or Jane…that actually matters less than you’d think. All of your shooting is going to be done at the range, so either accessory rail system will do what you need it to. If, however, you compete in 3-gun every week or are an actual uniformed officer upgrading your patrol carbine…you want the SOCOM-approved model.

What do you think though? Have a different preference? Used both and prefer one or the other? Have you finally accepted that hot wings should only come with blue cheese? Sound off in the comments!

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  1. In practice I’ve seen few of either at the range home to anything other than rail segments. Personally I like the Mad Max, warehouse shelving aesthetic of KeyMod but I don’t own any.

    • Ah, yes, the third paradigm in negative space rail mounting technology: KEYWORD!

      If I’m not mistaken, KeyMod was initially not open source and Vltor/Noveske essentially tried to monopolize the concept negative space mounting.

      They only made it open source pretty much after Magpul came out with M-LOK.

    • +1…that was the first thing that caught my eye…those lousy, lying, four-flushing keywords always inserting themselves where they’re not wanted…

      Back to the story…prefer M-Lok for all the reasons Sam elaborated (plus the fact that I support Magpul for their very affirmative 2A stance and politics). I’ve never had one work itself loose or break.

  2. And THIS may be the only decision I make on my no frills S&W Sport. The handguard sux and has no heatshield. Honestly may not even do that. Buyin’ a cheap red dot fer sure…

    • The cheap ($25) red dots work well, but you have to epoxy the optical glass into the frame. Apparently, that makes it a $100 red-dot – for $25 and 15 minutes of labor.

  3. If you want to remain undecided for a while, or have a box of accessories of various types, it’s hard to beat Manticore Arms’s Transformer forends. Bolt on whatever the heck mount you want – Keymod, M-Lok, Picatinny – in reasonable length segments, or polymer cover plates, or nothing at all. Get exactly what you want, where you want it.

    I’ve used OdinWorks’s Ragna rails – very lightweight, the barrel nut attachment is straightforward, and it’s a very unusual look if you care about that. They come in both flavors and various lengths.

    More recently I’ve started to work with SLR Rifleworks rails, and Faxon’s rails, both for the AR-10 platform. Some nice features there including built-in antirotation provisions “just in case.”

  4. You say that if you’re just an average joe, which one you pick doesn’t matter.
    My question is, why would you not pick the most sturdy option regardless of the use?
    If you pick something that didn’t last under stress testing, regardless of whether or not you plan on stressing it, I seriously question your decision making skills.

  5. I have a 15 inch Midwest Industries M-lok on mine. At least I did before the boating accident.
    Just dont like the look of the Keymod. I didnt know about the military picking M-lok until I read the article.

  6. My original choice was limited by price, didn’t have much money. I wanted free-floating and the ability to mount two items. A front sight and a forearm grip. Midwest had a quad rail that worked, I bought it, removed D-Ring and wave washer and fitted it to the gun.

    I say fitted it as it had some extra metal to remove or interfere with the lower, which surprised me. Bushmaster Carbon 15, a little thicker than mil-spec in places but damn it is light weight!

    So, money is a little easier now and I am reading all options with interest. Didn’t want the added weight of the four full rails. So now I’ll look at the options again, maintain free-float and look to weight, stiffness for adding a front MBUS and a mount for the grip.

    Could care less which brand or system I end up with, it’s all about MADE IN USA (always my first question), performance and price.

  7. USNavy CRANE did extensive testing of each, and picked M-Lok as superior in retention and maintaining zero.

    Ever since the CRANE report came out, KeyMod has been rapidly losing market share. The differences are minor enough that I certainly wouldn’t change out KeyMod accessories to M-Lok, but long term, M-lok is going to be the dominate standard. Thus a new buyer should probably go with the Magpull design.

    • I’m not making an argument either way, both are fine IMO, but the Crane testing was flawed. It hurts their credibility even more that they adapted what they wanted before conducting tests.

      More importantly, I hate blue cheese but I respect the author’s opinion and preference, until I have no other options.

  8. this is like arguing if the sun comes up in the east or not
    everybody already knows
    i choose not to participate
    i cant be part of it
    i wont

  9. But a single shot from a .45 will blow up your entire torso if it hits your pinkie. A piddly 9 wont do that!
    Oops. Wrong debate

  10. 1. 1913 quad rail is the strongest rail by far but you sacrifice some ergos. But if you want bombproof go with 1913.
    2. MLOK and KeyMod are identical for ergonomics but MLOK is stronger so go with MLOK.
    3. If you currently have some KeyMod rails continue to use them but buy either Quad or MLOK going forward.

    The DD RISII and M4 Quad rails are top notch. For MLOK, go with BCM, DD, KAC, LWRCI, Geissele

    there, all done.

  11. I wanted to put something here from a real operator not a paper puncher or a kid with too much money living in mommy’s basement… If you don’t know who Kris is kindly remove 80% of your man card and unsubscribe from all the gun stuff you watch.

    It has nothing to so with what company you buy stuff from or what is in style or how overpriced some lowers are, after all a lower’s only real purpose is to hold the f’ing hammer so it goes forward… argue all you want about tolerances and your $300 trigger. I’ve owned AR’s and NFA select fires for about 40 years and it’s not about the pretty FDE stuff you work into your basic black but it’s about the shooter behind ANY gun. I can’t count the number of times I’ve out-shot (and I’m only a medium-good shot) young and middle age out of shape ass clowns who “built their own AR”.. I usually ask them if they used button rifling in their barrel blank and air gauged it afterwards and they usually look confused and admit that all they did was put a Leggo kit together… I do that too but Ido not pretend to actually build a rifle, just put parts together with almost always perfectly adequate results. I can shoot a 32 pound (maybe an exaggeration) gritty military, pulling a sandbag over the tundra trigger gun better than most kids can flinch away with their $3,000+ custom anodized or Cerakoted AR’s.
    Yell all you want but please watch the video about a real man and his gun that has been everywhere.

    • George you are simply “the” man!!!! Well maybe a step below Kris there. You should get your own YouTube channel and show us some of that shooting you do.

    • Thanks for sharing the Tanto video. Very familiar with him but hadn’t seen this clip. It’s a good reminder. Probably convinced me not to make the next purchase I had been considering.

  12. Quad/1913 is still the clear winner in 2019. It is used way more than M-LOK and Keymod. It also tested better than both.


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