Who makes the best optic mounting screws?

[tlawler]

After shearing off the original S&W screws using the factory mounting plate, I purchased a C&H mounting plate, but the supplied screws were too long. I trimmed them down to the proper length and mounted the optic. Prior to mounting, I ran a tap down through the holes in the slide and degreased the slide. I applied fresh blue loctite on the screws and mounted to the proper torque. I thought everything was good to go, but after running 150 rounds through it, the screws started backing out. I tightened them at the range and ran another two mags. They were loose again when I finished. I went ahead and pulled the optic off and finished up the session with open sights. Anyway, now I’m looking at some aftermarket screws like Jagerwerks or similar and was wondering what everyone else was using that have gone to an aftermarket solution. I’ve got over 2K rounds through my M&P 2.0 10mm. Latest 200 rounds were 180 grain FMJFP over 9.3 grains Longshot, so they were some pretty warm rounds. Is the optic mount just not designed for that kind of abuse?

 

[cracker57]

try the red loc tight, if you ever need to remove it you can heat it with a hair drier or heat gun and it can be broke loss.

 

[tlawler]

try the red loc tight, if you ever need to remove it you can heat it with a hair drier or heat gun and it can be broke loss.

Thanks…I will. I do want to get some new screws first, though. Now that these have loosened up on me twice, I don’t trust their tensile strength. I just don’t want to go through the ordeal of sheared screws again.

 

[Rlg#17]

Idk who makes the best screws out there, but I have another suggestion for thread locker. The wife and I took an MOS operator course. Early on the first day the screws on her optic loosed. The instructor cleaned the threads with alcohol and reattached the optic using the wife’s fingernail polish. Just plain clear, cheapo fingernail polish.

After lunch she went back to using the pistol, roughly an hour to set up. Probably 750 rounds thru it after that. Since then she has over 10,000 rounds thru that pistol with zero fails. I’m going to redo all our optic pistols this winter with fingernail polish. Clear after cleaning the threads, torqued to 13”/lbs with just a dab of red polish on the screw head and optic housing as a visual confirmation that everything is tight.

Loosening doesn’t have any effect from tensile strength.

I have a few more rounds thru a G-40 of “hotter” Longshot loads then your number. At least 10 k, probably closer to 12k. Zero issues with the screws or loosening of the plate.

Good luck, I hope you get it straightened out. 10mm is da bomb!

Regards, Rick Gibbs

 

[markmiela]

I got some from swamp fox. They seem to fit nicely and you can get the kit.

Edit: I have not shot the gun with the optic mounted. But I did get the tip from a M&p forum on Facebook.


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[Ethang]

McMaster Carr but you would need to buy a box of 50.

I would not use red locktite. Blue is what you need and the stick kind will let you put it exactly where you need it. Make sure you degrease everything, slide, plates, screws and bottom of the optic. How long did you let it set up before you started to shoot?

 

[tlawler]

McMaster Carr but you would need to buy a box of 50.

I would not use red locktite. Blue is what you need and the stick kind will let you put it exactly where you need it. Make sure you degrease everything, slide, plates, screws and bottom of the optic. How long did you let it set up before you started to shoot?

It was at least a couple of days from when I assembled it until I went to the range. I’ve dealt with McMaster Carr quite a bit over the years…lots of good stuff, but I never thought of them for gun parts. I’ll see if I can track down a stick of blue loctite too.

 

[Ethang]

It was at least a couple of days from when I assembled it until I went to the range. I’ve dealt with McMaster Carr quite a bit over the years…lots of good stuff, but I never thought of them for gun parts. I’ll see if I can track down a stick of blue loctite too.

What optic are you using?

 

[Gman556]

I went to Permatex High Strength Orange Removable when my screws were getting loose with Vibra-tite, and also with blue Loctite.

The orange Permatex is stronger than blue Loctite but I have never had any issues getting the screws back out torqued to 15"lbs.

I may also start trying the above nail polish method.

Thanks for that!

I also noticed with the M&P 2.0 core, the threads go all the way through the slide, and oil will seep up into them and probably soak into the screws, degrading any thread locker which may cause them to back out sometimes.

When cleaning my slide I always try hard to make sure I don't let any lubricant go down into those thread holes.

 

[tlawler]

What optic are you using?

Holosun 507c

 

[Ethang]

Holosun 507c

Sent you a PM

 

[kstewart61]

A place called boltdepot.com has any size screw you need.

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[Racer X]

It was at least a couple of days from when I assembled it until I went to the range. I’ve dealt with McMaster Carr quite a bit over the years…lots of good stuff, but I never thought of them for gun parts. I’ll see if I can track down a stick of blue loctite too.

it's not a gun part, it's a screw that happens to fit a tapped hole in a S&W part. Sometimes we need to step back from a problem and actually define what the actual problem is.

loosening screw, and where to get more.

 

[Dave Lively]

Are you using a torque wrench?

If you hand tighten enough screws without one you will get a good feel for how much force to use. But you have to strip a few to know how much is too much. I don't deal with small screws often enough to get a good feel so I use a torque wrench.

 

[tlawler]

Are you using a torque wrench?

If you hand tighten enough screws without one you will get a good feel for how much force to use. But you have to strip a few to know how much is too much. I don't deal with small screws often enough to get a good feel so I use a torque wrench.

I didn’t the first couple of times I mounted it, but I’m going to pick up a FAT driver before I do it again. I ordered screws and a blue loctite stick from McMaster Carr yesterday. I’ll update when I get all the components together.

 

[Oldsalt66]

Are you certain that the mating surfaces were clean before applying the blue locktite?

Blue locktite is appropriate for that installation, I give it 24 hours to set.

Red locktite is overkill for small screws and it will prove problematic to remove them.

 

[tlawler]

Are you certain that the mating surfaces were clean before applying the blue locktite?

Blue locktite is appropriate for that installation, I give it 24 hours to set.

Red locktite is overkill for small screws and it will prove problematic to remove them.

I’m thinking I might have trimmed the screws shorter than I needed. They were bottoming out and I didn’t want to strip them out or shear one during installation, so I cut them a little shorter. After I cut them, I had only about .19” going down into the slide. I took some measurements with some longer screws, and found that I could go about .29” before the threads started binding. Measurements are from memory; I’m at work right now and have them written down at home.

 

[Racer X]

for proper thread engagement, you need the length at least as long as the width. So a 1/4-20 needs to have at least 1/4" thread engagement.

 

[tlawler]

I picked up the FAT wrench at Bass Pro yesterday and the screws and loctite stick got delivered this morning. I gathered all the components together and got to work. First, I gave the slide a good cleaning with Hoppe’s, then ran a tap down through the mounting holes to clean out the threads. I degreased first with mineral spirits, then HD Degreaser, letting it air dry well between degreasings. I dabbed the loctite on the lower two thirds of the screws and immediately ran them in. I finished off by torquing to 15 in-lb of torque with the FAT wrench. I’ll let the loctite set up for at least 24 hours before I take it to the range. Now that I have a plentiful supply of screws, I’ll be changing them after each 1K rounds. Does anyone have a different idea of change interval?

The screws are a little different than OEM. They take a T15 driver instead of the T10 that the OEMs take, which is ok because the smallest T-bit in the FAT wrench set is T15. The bits in the set are longer than standard bits and one of the standard bits I tried wouldn’t allow the FAT wrench to get a good square purchase to engage the screw head properly.

I’ll let everyone know how well it works.

 

[Ethang]

why would you change screws at a round count interval and not just when the optic was removed/installed?