SR762 Rear Takedown Pin

[ChaseFan9]

Several guys here have built off Matrix Aerospace receivers (the manufacturer of Ruger's receivers) and run into the same issue; the rear takedown detent spring is too short. I don't own an SR762 or I'd do it myself, but can anyone check and see how Ruger solved this problem?

Edited May 28, 2015 by ChaseFan9

[survivalshop]

 Look at post # 35 , this is one way , some drill& tap for a set screw . Check out the rest of this thread. 

 

 

[ChaseFan9]

I know, SS, that's why I started this thread, just in case someone with a Ruger missed it. Since the SR762 and Matrix set are supposedly the same set, I want to see if Ruger tapped the receivers or just use a spacer, or if they're even drilled for the rear takedown detent in the rear instead of the bottom of the lower.

Good looking out, though :)

[98Z5V]

If this comes up again - Ruger SR-762 lower receiver is identical to the Matrix Aerospace M-762 lower receiver.  I did this:

 

 

 

I tackled the Matrix takedown spring area this way - cut a second spring and stacked them.  i should have used a small washer to separate the two springs, but can't find a washer small enough.  I doubt the springs will connect (spiral together at the ends) based in the amount of movement there is there.  If they do, it's not a big deal, not a high-risk area.

 

I figured I needed the spring to stick out as much as it does on any other AR15 build, which is about this much:

 

 

I stacked the two springs together (detent and takedown pin in place), and just cut it off there.  Looked right.

 

Length on both springs, end-to-end:

 

 

Didn't feel like drilling the lower to use a 6-32 set screw, so I just ran the 4-40 tap in the stock hole - no drilling required to run a 4-40, if you decide that. 

 

 

4-40 set screw going in:

 

 

Done:

 

[blue109]

The LPK I got from Chris with my matrix lower had a correct spring. Its about 1 15/16" long.

[SaPPeR524]

solid fix, I like it