Slide mounted optic keeps coming loose

[Edwards30]

Hey everyone,

I am having a hard time keeping my screws tight on my slide and am wondering if I am missing something painfully obvious.

I am using an SRO on a Grey Ghost Precision slide.  I measured and shortened the longest of the screws and am getting maybe 3-4 threads of engagement without bottoming out or touching the extractor.

I have had this issue in the past so this time I de-greased the slide & screws with simple green, then did the same procedure with 90% iso alcohol, and finally applied #242 Loctite and used a Husky torque screwdriver to go to either 10 or 12 inch lbs (I don't recall what my research said).  I witness marked both screws and after 40 rounds one has already shifted.

Any ideas? The screws were new so I doubt they were stretched from 2 installs but maybe I'm wrong.
 

Edited December 11, 2021 by Edwards30
Edited so people didn't think I used ft-lbs

[AHI]

did you give the loctite 24 hours to cure?

[rooster]

Most failures of optics coming loose are in the installation procedure. However it sounds like you have done everything correctly. So that leaves the actual mount or the milling of the slide. Something is loose so that the optic is moving and coming loose. Instead of locktite try vibratite vc3 it’s a rubbery type locktite that has a cushioning trait instead of hardening. 

[Edwards30]

7 hours ago, AHI said:

did you give the loctite 24 hours to cure?

I actually gave it 48 before shooting or even dry firing with that one again. 

3 hours ago, rooster said:

Most failures of optics coming loose are in the installation procedure. However it sounds like you have done everything correctly. So that leaves the actual mount or the milling of the slide. Something is loose so that the optic is moving and coming loose. Instead of locktite try vibratite vc3 it’s a rubbery type locktite that has a cushioning trait instead of hardening. 

I did read a little bit about the VC3 and may give that a try. I’m also honestly considering a small spot of red instead as well. 
I ordered Jagerwerks screws but in the mean time I’m going to see if my optic is not warped or something else odd is happening. 
It can’t be a thread bottoming out issue as on the right side the whole goes straight through to the ejector channel and I’m not making contact with that. 

[zzt]

Do not use red.  Blue is fine.  So is the rubbery threadlocker.  If you have continuing problems with screws loosening, you are using crappy screws.  With the very best quality screws you hardly need Loctite.  All three of my open guns were frame mounts.  Good screws, no Loctite.

 

That being said, your mounting plate may have too loose threading.  You want 85%+ for security.

[Edwards30]

22 minutes ago, zzt said:

Do not use red.  Blue is fine.  So is the rubbery threadlocker.  If you have continuing problems with screws loosening, you are using crappy screws.  With the very best quality screws you hardly need Loctite.  All three of my open guns were frame mounts.  Good screws, no Loctite.

 

That being said, your mounting plate may have too loose threading.  You want 85%+ for security.

For this it is direct milled to the slide, so no plate. 
 

I have the optic off now and the threads look fine inside of the slide with no signs of old Loctite gummed in there. 
 

Sitting the optic on a glass table it seems to be square on the bottom with just slight movement. So like you said, I think I’m left with the screws. 

[zzt]

16 hours ago, Edwards30 said:

Sitting the optic on a glass table it seems to be square on the bottom with just slight movement. So like you said, I think I’m left with the screws. 

 

Just to be sure put a straight edge on the bottom and look at it from the side.  Move it around and over the bottom screws.  If you see any light you'll have to fix that first.  I had to sent two of my RTS2 v4s back because they could not be mounted correctly.  The screws holding the bottom plate on were not flush.

 

 

[Edwards30]

Another quick update if anyone cares to continue following along. 
 

I got new screws and repeated the procedures from before with the same result after 1 match of 270~ rounds. 
 

I have not been able to identify any sort of non-square edge on the slide or SRO. 
 

I’ve now ordered VC-3 and will start over. 
 

If that doesn’t hold I’ll start swapping parts and see if another SRO will fix the issue to start isolating it more. 

[zombywoof]

Try this, it works for me. Do everything you're doing to clean the threads and screws. My final cleaning is always acetone.

 

Use your blue loctite on the screw threads. I also get Gorilla glue construction adhesive. I spread it on the top part of the screw just under the head.

 

The loctite adheres the screw to the threads, the glue secures the screw to the body of the dot. Take a Q-tip and remove the excess glue around the screw after torquing.

 

The screws are easily removed.

[PaulZaccaria]

On 12/28/2021 at 7:12 PM, Edwards30 said:

Another quick update if anyone cares to continue following along. 
 

I got new screws and repeated the procedures from before with the same result after 1 match of 270~ rounds. 
 

I have not been able to identify any sort of non-square edge on the slide or SRO. 
 

I’ve now ordered VC-3 and will start over. 
 

If that doesn’t hold I’ll start swapping parts and see if another SRO will fix the issue to start isolating it more. 

So Im having the same problem mounting my SRO to a springer precision plate on my Sig X5 Legion.  Shook loose twice and broke the site.  Got another one and shook loose a third time.  I have mounted many red dots in my shooting career.  I tried everything and even talked with Springer.  No solution yet. Did you figure it out yet?

Paul Zaccaria A7588  paulzac55@gmail.com

[Edwards30]

34 minutes ago, PaulZaccaria said:

So Im having the same problem mounting my SRO to a springer precision plate on my Sig X5 Legion.  Shook loose twice and broke the site.  Got another one and shook loose a third time.  I have mounted many red dots in my shooting career.  I tried everything and even talked with Springer.  No solution yet. Did you figure it out yet?

Paul Zaccaria A7588  paulzac55@gmail.com

I went back and fourth countless times with CHPWS (They were excellent each time).  The last time I sent in my whole slide (stripped).  The screws were too long and hung up on my extractor after so I had to disassemble immediately.  

Anyways, after that time I ignored the torque reading and cranked down the plate as tight as I could, if I remember right, I did this out of anger.  Resulting in one of the screws to round off the Torx portion.  The threads on the screw itself held fine.  

So basically, I cleaned them again, added blue loctite, and just cranked them down.  It has been thousands of rounds since then and I haven't had an issue.