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Aftermarket sights

Posted: Mon Nov 05, 2018 2:02 pm
by Odinvalknir
I suppose this could apply to any handgun but I am specifically talking about my gun the M&P 9C. I have been carrying the gun for about 4 or 5 months, and recently decided to start changing this and that adding some Stuff Etc. I personalized in a little bit with a laser engraved rear slide plate, I added a + 3 round magazine extension, and finally I added fiber optic rear sights and swapped out the green sticks for black two black out the rear sights since I have trouble focusing on Purely the front sight when there is something else in between. I finally got to go to the range today and test out the rear sight and magazine extension. After about two magazines the rear sight had unscrewed itself and was sliding off to one side obviously making my rounds go Haywire. I'm wondering since this is just a set screw would it be beneficial to throw a little blue Loctite on the threads of the screw if that would help. I never had an issue with the stock sites coming loose not sure if I just did not screw them down tight enough or if they are just cheap garbage.


I guess my actual question is twofold, has anyone else experienced this and do you think putting Loctite on the set screw will stop from happening again. I did read tighten the screw after resetting the site and did not have an issue with it anymore for the rest of my time at the range.


Tl;dr : aftermarket rear sights screw came loose and sights started moving while shooting. Wondering if blue Loctite will stop this issue.

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 2:09 pm
by oljames3
Odinvalknir wrote:
Mon Nov 05, 2018 2:02 pm
I suppose this could apply to any handgun but I am specifically talking about my gun the M&P 9C. I have been carrying the gun for about 4 or 5 months, and recently decided to start changing this and that adding some Stuff Etc. I personalized in a little bit with a laser engraved rear slide plate, I added a + 3 round magazine extension, and finally I added fiber optic rear sights and swapped out the green sticks for black two black out the rear sights since I have trouble focusing on Purely the front sight when there is something else in between. I finally got to go to the range today and test out the rear sight and magazine extension. After about two magazines the rear sight had unscrewed itself and was sliding off to one side obviously making my rounds go Haywire. I'm wondering since this is just a set screw would it be beneficial to throw a little blue Loctite on the threads of the screw if that would help. I never had an issue with the stock sites coming loose not sure if I just did not screw them down tight enough or if they are just cheap garbage.


I guess my actual question is twofold, has anyone else experienced this and do you think putting Loctite on the set screw will stop from happening again. I did read tighten the screw after resetting the site and did not have an issue with it anymore for the rest of my time at the range.


Tl;dr : aftermarket rear sights screw came loose and sights started moving while shooting. Wondering if blue Loctite will stop this issue.
After about a year, I had Dawson Precision sights installed on my S&W M&P M2.0 9mm 5inch. I got the Charger set which has a fiber optic front, a black (no fiber) rear with the front face of the rear sight slanted forward to facilitate charging the pistol one-handed. The owner of my local training facility did the work. If I had done it myself, I certainly would have used Loctite.

Dawson Precision has tutorials and videos for installation: https://www.google.com/search?rlz=1C1WP ... sKwBCAMoAQ

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 3:06 pm
by AndyC
Shock will cause it to unscrew - I'd absolutely use Blue Loktite on it, yep.

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 4:18 pm
by Odinvalknir
I'm going to once I get home and get her all cleaned up, I wonder why S&W didnt design the slide where the screw actually screws into the metal of ththe slide. Even 2 threads into the steel would suffice, AND make it impossible to misalign the rear sight. From what I can tell there is plenty of material between the top of the slide under the sight and the internals of the slide. A set screw really seems to be less than optimal. My 1911s sights are attached more securely, I cant speak to glock as I've never owned one.

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 6:41 pm
by Jago668
If you don't want it coming loose, blue loctite. I put it on holster screws, sights, slings, etc. If I am going to bet my life on it, and it has threads, I put loctite on it.

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 6:46 pm
by Grundy1133
IIRC they put loctite on them from the factory. I have a full size but I put a dab of it on mine just to hold it in place after i replaced my plunger (which is under the rear sight)

Re: Aftermarket sights

Posted: Mon Nov 05, 2018 9:29 pm
by Scott B.
Sight set screws always get 243 Loctite when I do installations. The 243 has a little better temp resistance than the 242, but any is better than none.

Re: Aftermarket sights

Posted: Tue Nov 06, 2018 8:08 am
by Rob72
You didn't say what brand your aftermarket FOs are. Generally, you will find that aftermarket sights require some fitting, with a needle file, to fit the dovetail. If yours didn't, that's a bit unusual. In any case, no, set screws don't fit a slot in the slide, if they did, you would not be able to adjust the sight. I usually get the sights about where I think they should be and do a zero check at the range. If they're on-target, the set screw gets a good dab of LT red (271), and the screw is really snugged down.