The Magpul CTR stock is pretty popular. Thing is, I’ve noticed a lot of them, particularly in the commercial spec tubes, are loose and rattle a lot. So loose, in fact, that the friction lock lever doesn’t even do anything. Actually, with the four samples I had on-hand, only one had a lock that was doing anything, and all of them rattled. People are basically paying more for the same functionality as an MOE stock.
So I figured out a solution. You don’t need many tools, and it should take about ten minutes your first time.
Step 1: Punch out the lever roll pin.
Step 2: Remove the lever and push the detent out (I use a hex key here to apply pressure against the metal clip. The detent just pushes out)
Step 3: Take the metal clip, and with a vise/channel locks, squeeze the “wings” in. Go in small increments and recheck for fit.
Step 4: Reinstall the clip. Notice the increased gap here between the “wings” and the sides of the lever, compared to how it looked in step 2. This means it’s squeezing harder now.
Step 5: Reinstall the detent to hold the clip to the lever (already done in pic above), reinstall the lever, reinstall the roll pin. You’re done.
Again, as with any modification ever, go in increments and make small adjustments, instead of all at once.
Now go enjoy your tighter, play-free, quieter CTR. If this fix worked for you, spread the word.
Please leave any comments or suggestions – this is a constantly-evolving process!
The Turkey Shoot 
Excellent tutorial except for one point and that was removing the detent. Magpul must have changed the design a little and now there is no longer access from the end you show. In my case a hard shake and it fell out. Now my ACS locks up nice and tight! It was a bear getting out the roll pin that Magpul uses to lock in the battery tubes now so I could remove them to access the locking lever roll pin. All is good now!
As a follow up; I first measured the reciever extention flat and then measured the u shaped locking tab after removing it. Using those two numbers gave me the number I needed to achieve the tightness I wanted. In my case my target number (outside edge to outside edge) of the u shaped locking tab was .735 from .750.
All my Mil-Spec tube CTR’s fit rock steady right out of the box, but my recent Bushy build which calls for a commercial sized tube did not even contact with the compression lock engagement. Was totally bummed, as it was for all intents and purposes just an expensive MOE lol. Thank heaven for the WEB!! Your tutorial is super!!! You da man Buddy! after 3 increment tries (I went slow per your instructions) It is now as solid as a fixed one piece stock!! My face is hurting from the stupid grin that’s pasted on my face 🙂 Thanks for pioneering this fix; I truly appreciate the guts you had ground-breaking/attempting this solution and the time you invested to do the pictorial guide. You deserve all the props possible! Mahalo plenty, and all Aloha, Mike
Good day!
Maybe You know where from i can get this spare metal plate?
It seems i’ve broken mine…
Worked just as you described. Thanks!