KeyMod Vs M-Lok

[mtdawg169]

I have both and wouldn't recommend one over another. Keymod is easier to install

I'd agree with this. They both work well. Keymod is pretty darn easy and I've had good success with it for a couple of years now. Last year, I looked high and low for a 13" Geissele keymod rail. This was probably 6 months after they'd discontinued them. I manged to track down what might have been the last new one in the country. Glad I found it and still disappointed that Geissele doesn't make them any longer.

[patriot_man]

Today while installing a scout light mount I crushed and deformed 2 keyslots on my URX4.

I have to say I was not using much force at all (using supplied wrench) and I started to hear a crunch of aluminum. I took it off and found the back was deformed and the nut was damaged (not flat, nor circular in profile).

Edit: I just heard from KAC and apparently they had a bad batch of nuts. I'm currently in comms with them to resolve this.

[Slippers]

If you heard crushing, it usually means the recoil lug was sitting on top of the rail, instead of down in the keymod slot. This leaves a gap between the mount and the rail surface, so when you tighten the nuts, they deform and damage the rail.

Part of the strength of the keymod slot is provided by the accessory laying flush on top of it. As soon as you have a gap, the tapered shape of keymod nuts allows them to pull through the slot.

[mtdawg169]

Deleted.

[BoilerUp]

Today while installing a scout light mount I crushed and deformed 2 keyslots on my URX4.

I have to say I was not using much force at all (using supplied wrench) and I started to hear a crunch of aluminum. I took it off and found the back was deformed and the nut was damaged (not flat, nor circular in profile).

That sucks. Thanks for sharing, though, so others can learn from your experience and know to watch out for this situation when installing accessories. I thought the narrow slots would do a good job of ensuring the nut was in the correct location.

[patriot_man]

I just heard from KAC amd apparently they had a bad batch of nuts.

I'm currently in comms with them to resolve this.

[mtdawg169]

I just heard from KAC amd apparently they had a bad batch of nuts.

I'm currently in comms with them to resolve this.

Excellent news! Can you post up a picture of the nut by itself?

[patriot_man]

Excellent news! Can you post up a picture of the nut by itself?

[mtdawg169]

What in the world is going on there? The top ones are oblong compared to the pic rail nuts. Does the pic rail mount up correctly?

[Slippers]

Wow, that's really odd. At least it wasn't your fault!

[patriot_man]

What in the world is going on there? The top ones are oblong compared to the pic rail nuts. Does the pic rail mount up correctly?

I believe the nuts were originally flat but as a result of the improper heat treat they warped while I was tightening and caused the keymod slot backside to deform from uneven contact.

The pic section mounts fine. I've actually removed the staked screws to utilize the backer nuts on the scout light mount and it is fine!

Wow, that's really odd. At least it wasn't your fault!

Yup!

[urhero]

So a Facebook group I found seem to think keymod is junk and will fail pretty easily. What's your guys thought on their view? They seem to be pretty well liked from what I can tell

The problem with keymod is the way it's machined. There is less metal for support than there is with m-lok. For some this won't be an issue. If it's a rifle you take to the range and screw around with then probably no big deal. However, of it's a hard use gun that you're really putting to work and relying on, then why put yourself in a position where you're using a piece of equipment that has built in failure points.

Both are steps forward in terms of mounting accessories. The weight savings and size reduction over pic rail are great. Like I said though, if it's something other than a once in a while range gun you're probably better off going with m-lok simply because it's going to hold up better.

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[BoilerUp]

The problem with keymod is the way it's machined. There is less metal for support than there is with m-lok. For some this won't be an issue. If it's a rifle you take to the range and screw around with then probably no big deal. However, of it's a hard use gun that you're really putting to work and relying on, then why put yourself in a position where you're using a piece of equipment that has built in failure points.

Both are steps forward in terms of mounting accessories. The weight savings and size reduction over pic rail are great. Like I said though, if it's something other than a once in a while range gun you're probably better off going with m-lok simply because it's going to hold up better.

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I'm no metallurgist, but I don't think two hundredths of an inch of aluminum is going to make the difference between "hard use" and "range toy". M-LOK was designed with a larger minimum thickness because it was designed to work with plastic.

[mtdawg169]

I'm no metallurgist, but I don't think two hundredths of an inch of aluminum is going to make the difference between "hard use" and "range toy". M-LOK was designed with a larger minimum thickness because it was designed to work with plastic.

This. Mlok does have a higher pull out strength. But I'm not convinced that there's any practical difference. Mlok has surged for a few reasons. One, because it's new. And AR guys are suckers for new. Two, mlok has the power of Magpul marketing behind it. And no one does marketing as well as Magpul.

Let's face facts. Until mlok, Magpul accessories were solely for picatinny systems. And picatinny has been fading fast in the consumer market. If you're Magpul, that's a serious problem. Because demand for an entire line of accessories is shrinking rapidly. Problem #2? Keymod doesn't play well with plastic handguards. Solution? A new mounting method that works with your very popular handguard system.

Keymod was introduced with a single product, the NSR rail. Consumers and manufacturers who saw merit in the design, made it a reality. There was no one company pushing it.

I'm not saying that one is better than the other, because there are features in each that I like. And they each have their downsides. But people make too much of the "versus" argument.

[urhero]

M-lok provides flat engagement surfaces as opposed to the tapering that you get with keymod. It's that tapering that makes keymod more prone to slippage and attachment pullout

There's a reason that as manufacturers (Colt CA for instance) are doing their own testing they're choosing m-lok


In regards to the decision by Colt CA to go with M-lok for their MRR

"The decision to select M-Lok over its chief competitor, Keymod, was credited largely to M-Lok’s preference among Colt Canada’s LEO and military customers. However, additional performance metrics such as tear-off strength and ease of manufacture were also taken into account."

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