Pistol optic won’t stay tight on slide.

[rpenmanparker]

I installed a reflex red dot on my new 1911 .45 ACP. Doing so required having the dovetail insert for the mounting plate shaved a little to fit the rear dovetail. It was nice and snug she done. But even with about 15 inXlb of torque on the screws and blue Loctite, the optic continued to loosen from the mounting plate after about 25 rounds fired. The plate also loosened from the dovetail insert. Never had this problem on any gun with 9 mm, but I guess that is understandable.

I suspected the screw holes were too short before the screws reached the top of the slide to have enough threads involved and had my local gunsmith drill down into the slide and tap the holes to allow longer screws with more thread contact area. Coarser threads. Same torque and Loctite and still they don’t hold for a full box of ammo.

The gunsmith had done the last installation, so I have taken things into my own hands. Last night I super glued the optic to the mounting plate (cheap optic, no sweat there) to make sure there would be no slip between the two. Then I made sure the screws were not bottoming out, installed them with RED Loctite, and tightened them to a massive 45 inXlb. I would have liked to use some star washers but couldn’t make everything fit with them in the assembly. Fortunately the heads didn’t break off and the Torx wrench holes weren’t damaged. Good screws I guess. I won’t be able to shoot again until Monday. I will let you know what happens, but I am not optimistic.

If that doesn’t work, I guess I will have to have the slide milled for a more direct installation of the optic. If anyone has any other suggestions, by all means please let me know.

 

[a5werkes]

If you last efforts fail, consider using Loctite 620 which is designed for adhering small gap tolerances, 0.015", whereas the blue / red loctites may / will fail if the surfaces are not completely mated together.

 

[rpenmanparker]

If you last efforts fail, consider using Loctite 620 which is designed for adhering small gap tolerances, 0.015", whereas the blue / red loctites may / will fail if the surfaces are not completely mated together.

Thanks.

 

[rpenmanparker]

When I purchased my G23, it too came with the adjustable sights (the only G23 my local shop had available at the time). I had the same worry that you did concerning potential inconsistencies with the sight alignment.

I found that the best positioning of the sight was performed with the little flathead screws to the side of the sight. I centered the sight picture and also raised it up to the maximum height. For me, this was what achieved the best results. They stayed in position even after about a year of carry without any problems.

I recently changed them out for XS Big Dots and will install those night sights on any of my future carry weapons as well. I have shot better with the Big Dots than I had ever shot with that adjustable sight.

But as was said before, if you like those sights, just throw some locktite into the setting once you align it how you want it.

You misunderstand. I am not talking about the setting screws, but rather the screws that attach the optic to the mounting plate and the mounting plate to the gun. If the optic stays in place, the zero doesn't change on these optics.

 

[rpenmanparker]

No dice! I was shooting the 1911 .45 ACP today with the very tight screws. After about 25 rounds I checked the screws to see if they were loosening. They were still tighter than 15 inXlb. I shot some more and checked again. They were still tighter than 15 inXlb so I moved the torque screwdriver up a little bit to see if they were much tighter than that. But the screws sheared off. I suspect they were under too much tension at 45 inXlb over the weekend and just a little too much torque took them right off. Bottoms were of course left in the holes.

You know what? No big deal. I had already decided I really wanted to get the slide milled. I have already sent the slide off to Primary Machine in Morgan City, LA. I have seen good things about them online and will give them a try. They specialize in milling slides for optics and charge a very fair price, $160-170. They also sell popular optics at good prices. Hopefully the way they mill the cutout to just perfectly contain the optic will keep it from moving around and loosening the screws.

Stay tuned. I should have the slide back in a couple of weeks or so.

 

[rpenmanparker]

The gun is dark gray, and only the slide is getting Cerakoted as part of the milling job. I couldn't tell from the Cerakote color chart Primary Machine uses whether any of the shades of gray would be a perfect match. Of course that is doubtful so a harmonizing color makes more sense. At first I selected "Stainless Steel", but then decided I really didn't want that look. So I let Primary know I would prefer "Graphite Black". I think going darker instead of lighter will be the right choice.

 

[jmorris]

Any photos of the sight and how it installs?

 

[rpenmanparker]

Any photos of the sight and how it installs?

If you mean originally, no. It was a Sightmark Mini Pro Spec that I had attached via a Burris Novak dovetail mounting plate. When it kept loosening, I had the holes in the optic drilled down through the mounting plate into the top of the slide to firm things up. No dice. Since Primary Machine cuts the slide to perfectly fit the optic front to back to help prevent movement of the optic, I decided to switch to a Burris Fast Fire III. It is a better optic and is the same size as the Vortex Venom. So using that gives me ability to have better optics down the road without more slide cutting.