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View Full Version : Modular Rail mounting slot dimensions (multiple manufacturers)


Pyzik
29 April 2014, 08:15
I hope this thread can become informational to folks other than myself. But I need input from you if you have one of these rails.

Recently I was in the market for a slim rail system. I looked at Troy, VTAC, Samson, Midwest, Centurion, Odin Works and so on.

I ended up getting a pretty screaming deal on a Samson Evo 9ex. But, I don't care for Samson's covers compared to others and I don't know which other covers/panels will work and which won't.
I like the KAC URX panels. The Centurion CMR panels are nice too. Midwest SS panels seem like they'd be alright.
I am sure there are others I am not thinking of...

What I'd like to compile here his a comprehensive guide to multiple modular rails and their mounting slot dimensions.
So, for you guys running the aforementioned rails or similar rails can you post up dimensions?

Then I (or we, whatever) could add an image for each similar rail with mounting dimensions.
Out of all the standards for the rail I see (STANAG/NATO) I am not seeing a standard for hole placement for mounting rails to modular handguards.

MEASUREMENTS

Samson Evolution 9ex
https://lh4.googleusercontent.com/-ekFMRUQr4o8/U2EF4STUkLI/AAAAAAAABaE/ty5_5YOdaWw/w958-h310-no/Samson1.png

Midwest Industries Gen 2 SS
https://lh3.googleusercontent.com/-ECAK7z3un9Y/U2EIBSLKRmI/AAAAAAAABaM/JKH12EXP7JA/w958-h355-no/Midwest1.png

Centurion CMR
https://lh6.googleusercontent.com/-yVNMPhs0f4g/U2JP-EXGh_I/AAAAAAAABa8/pD4qIFlcEe0/w958-h312-no/CMR.png

Knight's Armament URX 3.1 After looking at the profile of the URX, I believe quite a bit of modifying will have to be done.
https://lh4.googleusercontent.com/-vcIgFBwkzfs/U2JSSn2xmvI/AAAAAAAABbE/Hd4RrKwDKUc/w957-h299-no/URX1.png


For further reference:

KeyMod
https://lh6.googleusercontent.com/-ZQF00Beaaps/U2JTPjHLD7I/AAAAAAAABbU/0AYJLkgvNq4/w755-h354-no/KeyMod.png
Pyzik
30 April 2014, 09:32
Added some measurements for MI Gen2 SS
UWone77
30 April 2014, 10:21
Interesting idea... I may have to break out the ruler.
Pyzik
30 April 2014, 11:52
Interesting idea... I may have to break out the ruler.

What rail do you have?

If you do, please post up the numbers.
Someone on my local forum gave me the MI measurement. I'd like to have a measurement for the slots too (distance between each and from the threaded holes, using center of radius).
UWone77
30 April 2014, 12:12
Which rail measurements are you looking for? I have rails... oh I got rails.
Pyzik
30 April 2014, 12:44
Which rail measurements are you looking for? I have rails... oh I got rails.

Haha.. Well, I really like the KAC URX panels and the Centurion CMR panels also look they may fit. So those are the two I'd really like.
Other than the missing data for the MI.
I can't think of any more that use holes or slots to install panels or covers. Do you know of any?

Key Mod and now the new MOE slots are open source, so we may see some panels for them as well (for aluminum rails like Geissele that are adopting it). But I have seen the measurements for them online.
Slippers
30 April 2014, 14:00
On the CMR the spacing between the holes are 20mm for the first three (for the CMR scout mount) and 40mm for the rest (for the CMR panels), or 0.788" and 1.57" respectively.

This spacing also corresponds with the 1913 picatinny spec, which is 10mm (0.394") from center to center on each slot.

Since some of the URX panels fit the CMR, it's safe to say that the hole spacing on the URX 3.1 is the same.
Pyzik
30 April 2014, 14:05
On the CMR the spacing between the holes are 20mm for the first three (for the CMR scout mount) and 40mm for the rest (for the CMR panels), or 0.788" and 1.57" respectively.

This spacing also corresponds with the 1913 picatinny spec, which is 10mm (0.394") from center to center on each slot.

Since some of the URX panels fit the CMR, it's safe to say that the hole spacing on the URX 3.1 is the same.

Thank you!
So it sounds like it would take more modification to get these to work with my Samson (though, just drilling a new hole in the panel).

I'll toss up an image of the CMR tomorrow. Headed to take the wife to fondle some pistolas. :D
Pyzik
1 May 2014, 07:17
Updated OP.

I also found this post that might be helpful to anyone in a similar position as me and I think I may give it a shot as well.

Modifying SCAR rail covers to work with Modular "slick" handguards. (http://www.m4carbine.net/showthread.php?130407-Centurion-Modular-Rail-(CMR)-picture-and-info-thread-(add-your-pics)&p=1654773#post1654773)



http://img.photobucket.com/albums/v483/militarymoron/cmr5.jpg