Adding flush cups to AIAE MK 3

Anchor Zero Six

Problem Solver
Nov 11, 2007
1,941
2
38
43
Corona Komifornia
#1
OK hiders I did some tinkering this weekend and figured I would take pics and post here of the process.

Google fu didnt return what I was looking for and that is a bolt on flush cup for my MK3. All I was able to find were side rails (W/O flush cups) which I thought was overkill to just be able to run flush cups. I would need to add a pic rail mounted sling mount and then be stuck with a considerable amount of real estate covered with cheese graters.

Looking at the skins there are removable covers over the holes which the rail hardware passes. Since there didnt seem to be an off the shelf solution I dove into my coffee can full of mist take off gun parts and came up with a simple, solid and I think elegant solution.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/BCC7C53C-4A1B-462B-8FBA-0687B5BB6EEF_zpsabxbptrw.jpg"}[/IMG2]
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I found some hardware from a Magpul VFG that came with a short section of rail to attach to the MOE handguards. I also found a Magpul flush cup. Think its called the "Type 1" they are $14.00 on Amazon I know this because I only had one and ordered a second.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/86A31ABB-B26A-4B30-964E-7CB3E413EC66_zpsaz29cor3.jpg"}[/IMG2]

The cap head screws that come with the Magpul wont work because the head sit to high to allow the swivel to engage. So a quick trip to the local ACE hardware yielded 10-24 countersunk 1/2" Phillips head stainless screws. Phillips were not my first choice but thats what was available. Cost was .37 ea. **EDIT** when I started this I was using parts from my spare parts box. When I received the new flush cup from Amazon it came with the proper allen head screws in two lengths. Also the current cups are deeper so the swivels engage with the cap head hardware no problem.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/D8A27942-E0F0-4129-96B8-2F95377F54DB_zpsbpxgc0ll.jpg"}[/IMG2]

OK so here are a few comments before I go further. First the hole in the chassis is slightly larger than the screw and I was a little worried about that but the backing plates have a flare on one side that actually centers it in the stock hole and supports it perfectly. Second and I cant stress this enough...have patience because getting the screw started while holding the backing plate with needle nose in the rail slot sucks balls and you will damage your children psyche if they are present with the cursing. Using a magnetic tip screwdriver is a must. Also I will tell you ahead of time you will need to file/grind one side of the plate to make it fit flush.

Back to the pics.

Flare

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/BA866AB5-2766-4C10-8DF7-6A040F99DFF0_zps0mimygzr.jpg"}[/IMG2]

Grind/file

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Red loc tight

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/03ED9167-9411-4D78-AFE5-81FBB55D140F_zpssl5jokse.jpg"}[/IMG2]

Assembled interior view. You could go shorter with the screw and I tried that first but the longer screw allows you to tilt it up which makes starting the threads easier because you dont have much room to work with in here.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/09475E92-013D-4EC1-BC0D-6B7561EF8112_zpslefyoig8.jpg"}[/IMG2]

Assembled outside veiws

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i238.photobucket.com\/albums\/ff193\/AnchorStation\/C26B1D48-8056-4BB6-9CD8-65BAD1266801_zpshbjcnqxi.jpg"}[/IMG2]
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So there it is, pretty simple non permanent way to add a flush cup (or two).

AO6

 
Last edited:
Jan 17, 2018
49
12
8
St. Louis, MO
#2
I found this thread from google and it is the best solution I have found to attach QD cups to legacy AICS. Photobucket unfortunately is a garbage website anymore and they broke all their links and riddle their sight with ads. I was able to recover all the photos above from broken links and re-hosted them on imgur. Below is the full post by Anchor Zero Six, thanks for posting this man, just wanted to fix it for all future searches.

OK hiders I did some tinkering this weekend and figured I would take pics and post here of the process. Google fu didnt return what I was looking for and that is a bolt on flush cup for my MK3. All I was able to find were side rails (W/O flush cups) which I thought was overkill to just be able to run flush cups. I would need to add a pic rail mounted sling mount and then be stuck with a considerable amount of real estate covered with cheese graters.

Looking at the skins there are removable covers over the holes which the rail hardware passes. Since there didnt seem to be an off the shelf solution I dove into my coffee can full of mist take off gun parts and came up with a simple, solid and I think elegant solution.





I found some hardware from a Magpul VFG that came with a short section of rail to attach to the MOE handguards. I also found a Magpul flush cup. Think its called the "Type 1" they are $14.00 on Amazon I know this because I only had one and ordered a second.



The cap head screws that come with the Magpul wont work because the head sit to high to allow the swivel to engage. So a quick trip to the local ACE hardware yielded 10-24 countersunk 1/2" Phillips head stainless screws. Phillips were not my first choice but thats what was available. Cost was .37 ea.

**EDIT** when I started this I was using parts from my spare parts box. When I received the new flush cup from Amazon it came with the proper Allen head screws in two lengths. Also the current cups are deeper so the swivels engage with the cap head hardware no problem.



OK so here are a few comments before I go further. First the hole in the chassis is slightly larger than the screw and I was a little worried about that but the backing plates have a flare on one side that actually centers it in the stock hole and supports it perfectly. Second and I cant stress this enough...have patience because getting the screw started while holding the backing plate with needle nose in the rail slot sucks balls and you will damage your children psyche if they are present with the cursing. Using a magnetic tip screwdriver is a must. Also I will tell you ahead of time you will need to file/grind one side of the plate to make it fit flush.

Back to the pics.

Flare



Grind/file



Red loctite.



Assembled interior view. You could go shorter with the screw and I tried that first but the longer screw allows you to tilt it up which makes starting the threads easier because you don't have much room to work with in here.



Assembled outside views





So there it is, pretty simple non permanent way to add a flush cup (or two).

AO6
 
Last edited:
Jan 17, 2018
49
12
8
St. Louis, MO
#3
Just ordered:

2x Magpul MAG333 Type 1 Sling Mount Kit
1x Magpul MAG406 MOE rail

The sling mount kits come with their own backing nut, however I wanted the flange style nut that AO6 used above. That's why I roderd the MAG406 kit was to get two of the flange nuts to help center the cup in the chassis hole.

I also found MAG332 which is a Type 2 kit. The MAG333 Type 1 kit simply has a through hole in it to insert a bolt through and thread into a nut on the back. MAG332 Type 2 kit is a threaded style cup. So you could order that and simply stick an allen bolt through back side of the chassis and thread the cup in from the open side. These were backordered so I opted for the Type 1 cups.

Seems like you could also order a Type 1 and a Type 2 kit then go to the hardware store and find a longer bolt. Mount the Type 1 cup, insert the bolt, it will go all the way through the chassis and then thread on the Type 2 cup from the other side to act like a nut to clamp it all down.

I thought about all the options but think the Type 1 with an MOE flanged nut is still the most robust. The flange on the nut helps center the cup and when you are pulling on the sling the force will transfer through the flange into the aluminum chassis. This prevents the threads from contacting the aluminum chassis during use.
 
Jan 17, 2018
49
12
8
St. Louis, MO
#4
Alright, just got done adding the Magpul QD sockets to both sides of the front of my chassis. Very happy with how this all turned out. Below are a few photos of the install.

On the left is the stock flange nut that came with the MAG406 MOE rail. On the right you can see how much material I had to remove to get it to fit inside the rail and butt up against two flat surfaces. I went pretty slow with a dremel and cleaned it up wth a small hand file. I continuously checked fitment until I was happy.



The QD kit came with a few different screw lengths and a small hex nut as well. I opted for the shortest screw as well as the modified flange nut from the MOE rail, shown on right.



The small raised boss around the threads on the flange nut fits inside the AICS chassis holes perfectly. Very happy with the fit. This boss is perfect to center the screw and the QD socket over the hole and transfer the load on the socket to the chassis without digging the screw threads into the side of the hole.



View from inside the chassis and how the re-profiled nut fits inside.



Here is the left side assembled. I was able to get my finger in the slot and hold the nut in place while I screwed the QD and screw in from the other side. The shortest screw has about 3-4 threads exposed.



View from the outside with how much the QD sticks out of the bare chassis.



Bolted the skins back on and plugged in a QD into the socket. Works perfectly. I'm still waiting on my barrel to arrive but the action, scope, and chassis weigh 10+ lbs and the single socket was holding all that up by the sling alone. Overall, it feels incredibly solid.



A few more finished photos of how it all fits together. Very pleased with this addition and it really brings the legacy AICS back to modern standards. Thanks to AO6 for coming up with this whole idea.



 
Last edited:
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