Optic mount won't stay tight

[hump]

My optic mount comes loose every 5-700 rounds. It is an Atlas mount on a SPS Vista Short 9mm. I have used blue and red loctite but still have issues. I have cleaned the mounting screws and frame prior to installing the mount several times. Any ideas.

[mro111lland]

Loktite the threads and the tapered part of the screw I use hi heat red loctite clean and dry they with a good carb clean tighten them TIGHT 

[Sarge]

14 minutes ago, hump said:

My optic mount comes loose every 5-700 rounds. It is an Atlas mount on a SPS Vista Short 9mm. I have used blue and red loctite but still have issues. I have cleaned the mounting screws and frame prior to installing the mount several times. Any ideas.

Are the screws correct? Are SPS metric? If screws are correct, all is cleaned and red loctite is used there is no reason for them to not stay tight.

[hump]

The screws are metric and are correct. I hesitated about using the red loctite because I knew how hard this stuff is to remove. 

[ChuckS]

Last time I had a mount go chronic loose, I found this:

[jcc7x7]

Clean , de grease, clean and de grease again.

Get the spray Loctite primer

A very light spray of the primer

1 small drop down in the threads and turn the screw in tight

Have the screw at the other end turned in for alignment purposes only with no Loctite on it for now.

Then do each successive screw until you get to your last screw you used for alignment.

Pull it out apply Loctite and turn it in.

NOW put it down and don't mess with it for at least an hour, longer is better.

Next day go shoot it and see if it holds , it should

[mro111lland]

5 minutes ago, hump said:

The screws are metric and are correct. I hesitated about using the red loctite because I knew how hard this stuff is to remove. 

Yes they are m3.5 mm screws what I have done is bought the 5x40 torques head screws for still guns ran them through a 3.5 mm die they come out perfect. When I thread them I only go as far as needed leave the rest the original thread diameter it takes up the slop in the hole.lok Tite them in if you need to remove them get a small butane torch like the novelty ones you can get at any c-store heat the head and the inside of the frame they come right out. It's worth the money to get the correct torques plus bit for removal it's not a normal torques bit is a torques plus any snap on or mac or matco dealer will have the or order one online. And yes I have a vista short and had the same problems. The other option is to have your frame drilled and taped to the 5x40

[Jfitz427]

That’s strange. I put blue loctite on my and set them and forget them. If red loctite wont hold them then there must be something else going on. That’s strong stuff. 

[hump]

Thanks for the replies. I will clean everything again, use the loctite primer and see what happens. I don't mind drilling the holes for a 5-40 thread if I have too. 

[funflyr]

I was having the same problem on a different gun. A gunsmith told me to clean everything really well and put a thin layer of red thread locker between the frame and the mount and then use the red on the screws. Clean off any thread locker that oozes out with a paper towel. I have shot 10k rounds through it and it's never moved.