[Sarge]

Since I have lost one set screw out of my rear sight on my M&P I had a question or two about setting it for good.

Which threadlock red or blue? I do want to remove it if absolutely need be but I don't want it to work loose again.

Is there a trick to keeping the sight from moving while removing the set screw to put threadlock on it? Or do I just mark it somehow and be gentle until I get it tight?

[yoshidaex]

Red will keep it in but to remove it you'll have to use some heat (not colorful inducing heat). Blue would work also but I would check the tightness after shooting a few matches to verify it'll retain the screw before calling it adequate.

[sheepdog]

Whichever you use, make sure it is not so much that it goes down into the firing pin plunger. Just heard about a case of that this week.

[B_Seehawer]

Whatever you do, DON'T USE GREEN!! Its wicking and will find its way into every crack and crevice. I'd personally use a tiny bit of red. Clean your threads out and go to town.

ganderman

[Dan Sierpina]

ganderman, on Aug 10 2009, 09:54 PM, said:

Whatever you do, DON'T USE GREEN!! Its wicking and will find its way into every crack and crevice. I'd personally use a tiny bit of red. Clean your threads out and go to town.

ganderman

Only 290 is wicking, the others are not.

[Dan Burwell]

Use the blue, only put a little on the threads not on the bottom of the set screw. I had to replace a bunch of parts on one not long ago because the owner used red, then needed to drift the sight a little, but he couldn't get it to budge so he put the heat to it. The problem was with the plastic liners inside the slide they warped pretty good.

290 may be the only one listed as wicking but they all do it to some extent. I have seen red and blue go from the set screw the whole way down to the plunger, since I didn't do it I have no idea how much was used to get it that far, but it happens.

[scheirere]

I second what Dan said. Blue (242) is all you need provided you clean the threads with something like alcohol or better yet, lacquer thinner. If you get all the oil and stuff off the threads, it will hold much better than you ever expected the "mild" 242 compound could. Also, the threadlocking compound adds a level of corrosion resistance that will keep steel threaded parts from making a permanent bond!

[Will_M]

Are you threadlocking an adjustable sight? Or the factory one?

[Dan Burwell]

Will_M, on Aug 25 2009, 10:38 PM, said:

Are you threadlocking an adjustable sight? Or the factory one?

The set screw not the elevation adjustment screw.

[Adrian_Sorah]

Could you just stake it?

[Dan Burwell]

Adrian_Sorah, on Aug 25 2009, 11:00 PM, said:

Could you just stake it?

Sure but that could be a real pain to get out when it is time to clean the plunger. Much easier to use a very small amount of blue loctite.

[SavageMOA]

Pardon my ignorance but the set screw is where now?

[Dan Burwell]

SavageMOA, on Aug 25 2009, 11:40 PM, said:

Pardon my ignorance but the set screw is where now?

in the factory rear sight it is visible from the top, in an adjustable sight you have to take the verticle adjustment screw out and lift the center portion up to get to the set screw. The set screw is there to keep the sight from sliding out.

[Will_M]

Dan Burwell, on Aug 25 2009, 10:45 PM, said:

SavageMOA, on Aug 25 2009, 11:40 PM, said:

Pardon my ignorance but the set screw is where now?

in the factory rear sight it is visible from the top, in an adjustable sight you have to take the verticle adjustment screw out and lift the center portion up to get to the set screw. The set screw is there to keep the sight from sliding out.

Is the rear sight sliding out a common problem with the M&P?

[Dan Burwell]

Will_M, on Aug 26 2009, 01:53 PM, said:

[Is the rear sight sliding out a common problem with the M&P?

not at all, in fact they are quite difficult to get to go anywhere from the factory.

[Sarge]

Will_M, on Aug 26 2009, 01:53 PM, said:

Dan Burwell, on Aug 25 2009, 10:45 PM, said:

SavageMOA, on Aug 25 2009, 11:40 PM, said:

Pardon my ignorance but the set screw is where now?

in the factory rear sight it is visible from the top, in an adjustable sight you have to take the verticle adjustment screw out and lift the center portion up to get to the set screw. The set screw is there to keep the sight from sliding out.

Is the rear sight sliding out a common problem with the M&P?

Don't know if it's common but mine lost the set screw and just about fell off before I caught it. There was nothing on the threads so maybe they missed the loctite step on mine. When I sent the gun in for FTE issues I had them replace the screw. They put on a new sight and gave me a few extra screws with loctite on the threads already. Unfortunately the sight they put on has a really crappy finish on it compared to the one they took off. But at least it's tight.

[Dan Burwell]

sandman, on Aug 26 2009, 04:16 PM, said:

Don't know if it's common but mine lost the set screw and just about fell off before I caught it. There was nothing on the threads so maybe they missed the loctite step on mine. When I sent the gun in for FTE issues I had them replace the screw. They put on a new sight and gave me a few extra screws with loctite on the threads already. Unfortunately the sight they put on has a really crappy finish on it compared to the one they took off. But at least it's tight.

That is weird, the screws they use have that nylon patch on them so they don't have to put loctitie on there. I supose they could have had a screw that didn't get the patch, but certainly not a "common" problem

[Sarge]

Dan Burwell, on Aug 26 2009, 04:19 PM, said:

sandman, on Aug 26 2009, 04:16 PM, said:

Don't know if it's common but mine lost the set screw and just about fell off before I caught it. There was nothing on the threads so maybe they missed the loctite step on mine. When I sent the gun in for FTE issues I had them replace the screw. They put on a new sight and gave me a few extra screws with loctite on the threads already. Unfortunately the sight they put on has a really crappy finish on it compared to the one they took off. But at least it's tight.

That is weird, the screws they use have that nylon patch on them so they don't have to put loctitie on there. I supose they could have had a screw that didn't get the patch, but certainly not a "common" problem

Hey Dan, I am sure it was a fluke. But it sure is funny now in retrospect. I was trying some new loads and it was shooting 2 foot groups into a hillside from the draw. Man I thought I sucked big time. I was going nuts until I just happened to notice the sight picture looking a little funny and reached up and slid the sight back and forth.