[mikemp40]

Just a question for those of you with more experience than I have. I bought a MP .40 a few months ago and I love it, however, I have noticed that the front sight is very loose. I can actually remove it and put it back with almost no force using just my fingers. I am thinking of getting an aftermarket sight for it anyway and was wondering if this is something I should have looked at before I get the new sight, or will the new sight fit properly? Also, what aftermarket sights will work with the factory rear sight? Any insight and wisdom is greatly appreciated.

 

[TOF]

Hey Mike, I had one loosen on my 9mm so simply removed it all the way, cleaned with acetone then added some locktight (blue) pressed it back to center and let set overnight. That sight will not loosen withought significant effort being expended. Blue Locktight is considered to be permanent. After overnight cure you can loosen the set screw on the rear sight and drift it with a brass punch to set windage then re-tighten set screw. Don't use Locktight on rear.



Some aftermarket sights will require filing or sanding to custom fit and others might press right in. I reccomend Locktight be used, either blue (permanent) or as a minimum red (not so permanent) on the front sight.



Good luck.

 

[coltman1985]

There have been many complaints about M&P front sights being way to tight. First time I have heard that the fronts are so loose. I recommend reinstall with red loctite. New sight, I recommend changing front and rear to Dawson Precision's, but the front will requiring some fitting.

 

[tschmittel]

I think it's the opposite. Red permanent, blue not so.

 

[Dan Burwell]

Neither are permanent Red just takes heat to break it free blue does not.



There was a few in the serial number range MPBs that got out with a dovetail that was not cut correctly and allowed the sights to come loose very quickly. You can tell if you had one as there was a visible trough down the middle of the front dovetail. It was maybe 0.002 deep, just deep enough that locktite would not likely hold it for long.

 

[Joe Long]

Use Loctie 262 or stronger. As Dan said, neither is actually permanent. The blue is a bit weaker, and is nowhere near as heat resistant. I highly recommend using loctite on both front and rear sights. Once you have the windage set, just apply two drops into the dovetail on the left side of the rear sight, let it sit for about sixty seconds, wipe it off and go. It'll need an hour MINIMUM before handling and shooting, and preferably overnight. Once you've applied the loctite, the sights aren't likely to move.



Monte

 

[TOF]

I think it's the opposite. Red permanent, blue not so.

Correct. My feeble old mind gets confused these day's. I just looked at the bottles and Blue is the "Removable" one. I used Red on my front sights.



My 9mm which loosened up is in the MPB9xxx series. I will have another 1000 rounds through it in a couple of weeks and will let you know if it shifts due to firing stress.



:twisted:

 

[mikemp40]

Thanks a lot for all of your information. I got some locktite today and took care of the problem.

 

[Angry_American]

I know I am abit late on this one, but did you consider sending it in to S&W and have it fixed under warranty? I sure as heck would, thats a big no no.

 

[JDLSALES]

There was a time when the M&P sights on many guns were very loose front and rear. The rumor is the fix S&W used for this complaint was to lock the sights in with super glue. Now the complaint is the sights are too tight and almost imposable to replace. Case in point the last sights I replaces I had to use nail polish remover before I could get the sights to budge.

 

[coltman1985]

My M&P40's sights where so tight that I thought it my be related to my wife!!

 

[Effyouess]

I had the same problem with my 9mm. I had a gunsmith tap it from underneath, and set the sight with some locktite on it and I've had no problems after 2000+ rounds.





Ciao,

Effy