M&P 2.0 Shield

[Lindy]

I recently picked up a set of Trijicon HD's, yellow for my shield. I had a LGS friend install them.

Went to the range today and about 200 rounds in things went left. I look down and my front site was coming out to the right. I was able to push it all the way out with my hands.

I get home and take a look. Slide and sight look fine, as in neither looks like they were filed or marring or anything that would suggest an issue or excessive force was used, just pushed on.

I can push the sight 3/4 of the way back on before it stops but need tools to go any further. The old sight, which was hard to get out, according to the LGS friend, goes in about 1/3 before I need tools.

I have some brass/polymer punches and a vise with padding, so putting it back on is not that big of a deal. I was thinking about using some loctite, does anyone have suggestions as to which color (blue/red etc)?

Thanks!

 

[CB3]

I wouldn't use Loctite. It's not really appropriate for this application.

Aftermarket sights are generally made with generous tolerances so they can be fitted properly to milled dovetails that will have minor variations. A good gunsmith will sand off a little of the bottom surface of a sight to lower it in the dovetail until it is just right. Sounds like your fella may have overdone it and the sight is now too loose.

If the sight is blued the bottom should be blued too if it is untouched. If you see that the bottom of the sight is bright and shiny, that is an indication it has been sanded/filed (too much).

Your options include:

Return it to your gunsmith for repair/replacement at no cost.

Take a pointed cold chisel and raise a few rims on the bottom of the sight. When you first try to insert it it should go in no more than 1/3 the way. You should need force beyond that point to fit it securely. If your rims are too tall to even get it 1/3 the way in, sand a LITTLE at a time off until you get to the 1/3 magic insertion point. [This is what the gunsmith will most likely do.]

 

[Lindy]

Thanks. I will take it back to him.

 

[Real Old Navy]

I had TruGlo TFO sights installed by a certified gunsmith at a LGS...along with an Apex striker block for $35 labor. He used blue Loctite and laser bore sighted my 9mm 1.0 Shield. Guaranteed or bring it back for any adjustment...didn't need to.

 

[CB3]

After Googling using thread lockers in dovetails, I see many do. I use it on any screw on a gun, including a sight (set) screw or Glock front sight. I’ve never installed TruGlo sights so maybe they fit differently.

A properly fit friction/press fit dovetail sight should work without additional security. IMO thread locker would just goop up a universally successful mounting method and make the sight even more difficult to remove.

Disclaimer: my sight mounting skills were learned here on this forum because S&W factory sights are often very, very difficult to remove. I use a sight pusher. I am not a gunsmith, but I have removed/replaced a few dozen sights that have stayed exactly in place and were able to be moved if necessary, without thread locker in the dovetail. YMMV.

 

[Lindy]

Went to the gunsmith this morning at 9am. Talked to him about the options. He strongly suggested red loctite based on the fact that it takes a tool to completely get the sight in. He said that if it needs a tool then there is enough traction and I do not need to dimple the bottom or dovetail face to create more traction. He says we need to get loctite in between the dovetail contact points and that it is no different than a threaded screw. I went with that option and he let me watch him do it back at his bench.

Basically cleaned everything really well with some chemical. Set the slide in a vise with ruber/plastic guards. Liberally applied red loctite to the slide, basically blobbed it in the slide dovetail, pushed the sight in to its stopping point and used a aluminium punch that has a nylon tip to center. Measured a few times with a caliper, tapped, measured, done. The red loctite was all over the front coming out of the dove tail. He let that sit for about 5min while we talked, then he wiped all of the excess off. He told me to let it cure for 48 hours before using the gun.

He also told me if I wanted to, too pickup some loctite 620 and after 48 hours, to put it on both sides of the sight in the dovetail and the tiny gaps on top (between the sight and the slide). He said that 620 was much stronger than the red (272?) and that it would lock the sight in place so the red never gets stressed. I asked him why he did not use the 620 in place of the red and he said it would make it almost impossible to get the sight out if it was under and in the dovetail channel. It would take a torch and probably ruin the sight if I had to get it out. He said the red will weaken if I apply a flat tip soldering iron to the base of the sight/slide and let it sit for 5min. Weaken enough that I could then get the sight out with some effort.

I just ordered some Loctite 620 Retaining Compound, $26 for a small 10ml bottle. I am not sure it I want to put it on the sides. I think I will shoot first to make sure all is good then apply it.

 

[CB3]

Went to the gunsmith this morning at 9am. Talked to him about the options. He strongly suggested red loctite based on the fact that it takes a tool to completely get the sight in. He said that if it needs a tool then there is enough traction and I do not need to dimple the bottom or dovetail face to create more traction. He says we need to get loctite in between the dovetail contact points and that it is no different than a threaded screw. I went with that option and he let me watch him do it back at his bench.

Basically cleaned everything really well with some chemical. Set the slide in a vise with ruber/plastic guards. Liberally applied red loctite to the slide, basically blobbed it in the slide dovetail, pushed the sight in to its stopping point and used a aluminium punch that has a nylon tip to center. Measured a few times with a caliper, tapped, measured, done. The red loctite was all over the front coming out of the dove tail. He let that sit for about 5min while we talked, then he wiped all of the excess off. He told me to let it cure for 48 hours before using the gun.

He also told me if I wanted to, too pickup some loctite 620 and after 48 hours, to put it on both sides of the sight in the dovetail and the tiny gaps on top (between the sight and the slide). He said that 620 was much stronger than the red (272?) and that it would lock the sight in place so the red never gets stressed. I asked him why he did not use the 620 in place of the red and he said it would make it almost impossible to get the sight out if it was under and in the dovetail channel. It would take a torch and probably ruin the sight if I had to get it out. He said the red will weaken if I apply a flat tip soldering iron to the base of the sight/slide and let it sit for 5min. Weaken enough that I could then get the sight out with some effort.

I have to disagree. From your description there obviously was not enough friction to keep the sight unmoving in the dovetail. Relying on excess Loctite of two different types to do the job is a real chewing gum fix.

This gunsmith’s solution to originally mounting your sight too loosely—without Loctite—may work fine, but a stopped clock is right twice a day. There are right ways and wrong ways to mount sights professionally, and it just doesn’t sound to me like he used the best professional methods either time he serviced your gun.

I would not accept a sight mounted by a gunsmith who gooped it up with Loctite to hold it in a dovetail and then recommended you go home, buy your own stronger goop and slather on top of his.

Nope. Nope. Nope.

 

[Real Old Navy]

IMO the blue Loctite should have been enough to hold it in place, providing that the dovetail is clean of any oil or grease...just a little dab will do ya...the red and 620 is overkill and if that sight needs adjustment it's going to be a pain in da butt. Even after measuring it with a calipers, I hope he laser bore sighted it?

 

[Lindy]

I have to disagree. From your description there obviously was not enough friction to keep the sight unmoving in the dovetail. Relying on excess Loctite of two different types to do the job is a real chewing gum fix.

This gunsmith’s solution to originally mounting your sight too loosely—without Loctite—may work fine, but a stopped clock is right twice a day. There are right ways and wrong ways to mount sights professionally, and it just doesn’t sound to me like he used the best professional methods either time he serviced your gun.

I would not accept a sight mounted by a gunsmith who gooped it up with Loctite to hold it in a dovetail and then recommended you go home, buy your own stronger goop and slather on top of his.

Nope. Nope. Nope.

Well I agree with him in that the sight required a tool to get to the center position. He or I could not, with much force, push it by hand into place. That means that there is real metal on metal contact in the dove tail. Gooping it on ensures it gets under and in the dovetail completely. He wiped the excess off and looking at it now you can't even tell there is any on it.

He also did not think I needed 620 but that some people did this and suggested it as an option. He actually said if it comes lose with the red, that he would contact Trijicon and ask for a new front sight as he did not have to file the sight at all.

Searching on the Internet the use of loctite and the 620 formula is quite popular on front sights.

From the maker of Dawson Precision sights....

[ame]https://www.youtube.com/watch?v=z95rJxs5-GQ[/ame]

They even sell it...specifically for front sights

https://dawsonprecision.com/loctite-adhesive/

Other links....even from this site

http://smith-wessonforum.com/smith-wesson-m-p-pistols/520424-setting-up-front-sight-m-p9c.html

https://www.m4carbine.net/showthread.php?185626-M-amp-P-owners-front-sight-walking-fix

If it holds I am good to go, and I personally think it will. If not I will have him contact Trijicon. He says they wont hesitate to send another out because they have great customer service.

 

[Lindy]

IMO the blue Loctite should have been enough to hold it in place, providing that the dovetail is clean of any oil or grease...just a little dab will do ya...the red and 620 is overkill and if that sight needs adjustment it's going to be a pain in da butt. Even after measuring it with a calipers, I hope he laser bore sighted it?

No laser bore. When I went to the range before it moved it was dead on at 7 and 10 yards. He put it back to center again.

If it was off for some reason I could drift the rear. I would rather center the front and adjust the rear. All that said we are talking a Shield with a 3 inch barrel and fat combat sights, the whole setup is CCW close up defense setup, not a target shooting rig. I was nailing a 6inch plate rack at 15-20 before the sight moved, which is fine by me.

 

[Lindy]

230 rounds this morning. Sight did not move a mm. Red Loctite is a winner.

 

[ROB94045]

I guess I was fortunate. I bought an inexpensive (but reasonably solid) sight pusher on eBay and installed the TruGlo TFX Pro sights on my XDm-40. It worked quite well. The toughest part was pushing the original sights out. They were extremely tight. I wound up removing the slide, putting a little penetrating oil on the sights and leaving it in the freezer overnight then pushing the sights out immediately after taking it out of the freezer. I used a slight amount of blue Loctite because the blue is generally removable where the red is intended to be permanent. I used a cheap laser bore sight from Amazon and it's right on.

But after doing that, I'm glad that my PM40 and my Performance Center Shield both came with Tritium sights from the factory.

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