How to: Adjust the friction lock on Magpul STR

[titanse05]

Well I was one of the first people to purchase a Magpul STR when they first came out and I immediately fell in love with it. It is a great stock and I found the cheekweld very comfortable. The only issue that I had with the stock was that the friction lock did nothing to "lock up" and make the stock rock solid on the extension like the CTRs do. So last week I figured that I would fix it myself and lucky for you I took some pictures along the way. I am pleased with the fix and now the stock only slightly wiggles due to the size of the slightly oversized hole at the extension.

Tools needed:
Drill
1/8" drill bit
Flathead screwdriver
Needle nose pliers (preferably locking)
Hammer
1/8" punch
Rivet tool
1/8' dia. 1/4" grip

In order to get to the roll pin that the friction lock pivots on the storage tubes need to be removed.

Directions:

Step 1: Remove the buttpad and rubber storage tube caps. This reveals the factory rivets that will need to be removed to take the storage tubes off.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_124707_zpsnx20vilr.jpg

Step 2: Using the drill equipped with the 1/8" bit, remove the head of the rivet. Then use your flat head screwdriver and gently pry the storage tube away from the rivet. With this rivet removed you can then slide the storage tube off by pushing on the flat area at the front of the tube towards the rear of the stock. Do this on both sides.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_124811_zpsnddxpcul.jpg

Step 3: With the storage tubes out of the way, use your screwdriver and pliers to remove the remaining part of the factory rivet so we can re-rivot it at the end.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_124843_zps8zbssqdj.jpg

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_125407_zpswlwmdfd5.jpg

Step 4: Using a hammer and 1/8" punch, remove the roll pin retaining the friction lock.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_125631_zps8k3xipqr.jpg

Step 5: Remove the black pin that is retaining the metal clip in the friction lock. I just pushed the metal clip towards the direction of the pin and it just slid out.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_130115_zpscesi0zpg.jpg

With the metal clip removed you can see that the metal clip is supposed to provide the additional clamping action on the plastic tabs on the stock to provide the friction on the extension to lock it.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_130715_zpsafqpk2gh.jpg

Step 6: Take your pliers or use a bench vise and push the ears of the metal clip in slightly. This will give us the additional friction we want. Don't go too crazy and incredible hulk and destroy the metal clip, a little adjustment is all that is needed here.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_130715_zpsafqpk2gh.jpg

Step 7: Now we can put it all back together the same way we took it apart. Now it may be necessary to place the stock on the extension and reinstall the friction lock while installed depending on how much you bent the ears in.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_130804_zpsjikmfaie.jpg

Step 8: Reinstall the storage tubes and buttpad. Rivet the storage tubes using 1/8" diameter, 1/4" grip rivets.

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_195302_zps3bxnh38q.jpg

http://i230.photobucket.com/albums/ee318/titanse05/Gun%20stuff/20140301_195316_zpsixfycvwt.jpg

Step 9: Pat yourself on the back and enjoy your STR and it's newly added friction lock feature.

[GOST]

I used to have a STR and honestly never thought about doing that. Very nice tutorial, good job titanse05.

[UWone77]

Is having to adjust the friction lock a wide spread issue?

[Slippers]

I can say that my STR is very loose. The friction lock doesn't serve any purpose. Not sure I care enough to try to fix it, though. Not like it rattles when I'm down on it shooting.

[GOST]

Idle hands are the devils workshop.... titanse05 is just trying to stay busy.

[titanse05]

Is having to adjust the friction lock a wide spread issue?On a lot of the STRs I think it is. The explanation that I have got from Magpul Reps was that the tolerances were increased on the STRs friction lock to accommodate a wider range of buffer tubes. If they would have kept the same tolerance as the CTR this would probably be a non-issue.

I have two STRs, one on a Mil-spec Rainier Arms buffer tube, the other on a Mil-spec BCM buffer tube. I made this adjustment on the STR that was mounted on the RA buffer tube, but the one on the BCM buffer tube locks up perfect.