Typical thickness of a M-LOK handguard?

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338_Lapua

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Jun 27, 2025

#1

• Jun 27, 2025

• #1

Anyone happen to know the typical thickness for a M-LOK rail?

The only source I could find online said 1/8 inch thick, or about 4mm in the description.

That seems a little thicker than I would have expected. Generally they appear to be around 3mm from what I've seen.

Unfortunately I don't have a specimen handy and the M-LOK specifications don't seem to specify the thickness anywhere.

If anyone could put their calipers on one and check I would much appreciate it.

 

TonyTheTiger

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I've got a bunch of them, and while I've never measured I know the thickness varies considerably because when I'm swapping accessories the screws need a lot adjusting to go from one rail to another.

 

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roostercogburn98

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#3

• Jun 27, 2025

• #3

TonyTheTiger said:

I've got a bunch of them, and while I've never measured I know the thickness varies considerably because when I'm swapping accessories the screws need a lot adjusting to go from one rail to another.

Click to expand...

Plus one here,

I’ve got plenty of different sized ones

 

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338_Lapua

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#4

• Jun 27, 2025

• #4

TonyTheTiger said:

I've got a bunch of them, and while I've never measured I know the thickness varies considerably because when I'm swapping accessories the screws need a lot adjusting to go from one rail to another.

Click to expand...

Good to know! Do you have any that are 2.5mm or 3mm thick?

 

TonyTheTiger

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#5

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338_Lapua said:

Good to know! Do you have any that are 2.5mm or 3mm thick?

Click to expand...

Just measured 7 handguards randomly, they were actually all 2.5-3.1mm thick.

 

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338_Lapua

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Jul 6, 2025

#6

• Jul 6, 2025

• #6

TonyTheTiger said:

Just measured 7 handguards randomly, they were actually all 2.5-3.1mm thick.

Click to expand...

Thank you so much, exactly the info I needed!

 

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mark5pt56

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#7

• Jul 6, 2025

• #7

Be mindful when choosing rail covers, I do know that the Vision Hybrid is to thick for Magpul Type II covers to work. Anything with the tnut set would be ok though.

 

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Green461

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#8

• Jul 7, 2025

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I wondered the difference between the expensive ones and cheap ones also.. I measured 5 of mine. In inches, this is America. lol.
Midwest industries - .100
Aim Sports - .085
Durkin tactical ($15 clearance) - .100
Durkin tactical ($15 clearance) - .085
Guntec - .085

I think i picked up 4 from Durkin when they clearanced them. I've handled many at gun shows, stores, I didnt know there were diffrent thicknesses till now. Cant really tell a difference (thickness wise) Even high dollar ones they all seem to be about the same thickness. Finishing is a huge difference. Some of the cheaper ones they dont smooth the edges of all the holes and they are sharp.

 

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SpeedyR

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Jul 9, 2025

#9

• Jul 9, 2025

• #9

Not sure i've seen an actual spec from Magpul but I assume there is one out there. The majority of the rails out there from main brands are 2.5-3mm thick. There are a few that are quite a bit thicker (MDT is one) where they are not concerned with weight. Most that I have are closer to 2.5mm thick (LMT, SOLGW, Geissele)

 

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