Hey guys. Installed hiviz fiber optic sights a few months ago on my m&p 2.0. I have a brass drift and 3 nylon punches which I used to install them. The rear sight went in fairly easy but the front sight was a bear! I sanded off the bottom of the front sight and it installed, but very tight. Took a good bit of whacking with the brass drift. The new sights I bought are trijicon hd. Should I be able to push the front sight halfway into the dovetail this time around? Would that create enough tension in the joint to keep it in place without loctite? Now that I've installed one set (twice) I understand a bit more. Help!

If you want to fit them without Loctite, you need to either file or sand the bottom or file the dovetail angle so they are a light press fit. This means that they drive into the slot with only medium strength taps, not hard blows. If you want to go the easy route, file for a slip fit, then use red or green Loctite to hold in place. Properly done, neither one will move unless you want it to.

Do you think measuring with a digital caliper and filing down to that and then taking off small increments would also work well? So i would pretty much want to be able to install the front sight with the nylon punches (they chip if you hit that spot where the sight stops moving) only? So as easy as the back sight fits in? I know the stock trijicon sights i have on my shield are said to be a big pain in the butt to remove, is that because they use a machine or is that how tight they have to be not to walk in the near future? I was so scared to take off too much the first go around so i sanded it until it slipped in 1/3 the way or so and pounded it in the rest of the way. Actually dented the brass punch a bit.

The M&P Front sight slot is not machined flat, but is higher in the middle. And they press the sight in with a machine at the factory. It is a PIA, but you need to do serious fitting so YOU DO NOT pound on the night sights. I put a fiber FO in a German made .22 in 30 minutes, but it took me over two hours of filing to do the same on my Shield.

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Science plus Art

Yes i did notice the step in the center. It looks like they mill the sides down in the dovetail. The rear sight on my shield when i did my apex trigger as well as on my 2.0 i remember it pushed in most of the way with my finger and then i tapped it in the rest with the nylon punch. BUT the rear has a set screw, which is what makes me nervous about removing too much from the front sight since it does not. I have a nice set of nicholson files, would those work well? Should i use a diamond stone? Sandpaper? I used sandpaper the first time but it seemed like it took forever and finding a flat surface was gun as well. I don't really care if i damage the sights that are on there now removing them so i'm not concerned with it being a pain to remove the ones on there now. They say it glows for what, 24 years and they promise you'll get half that out of them? By the time 12 years passes i'm sure they'll have better sights out anyways lol.

Wish me luck, sights will be here in the next few hours! I'll post up some pictures if they go in without a problem lol.

OK, you don't mention which direction you're moving the sights. From the rear of the slide, S&W sights go in from the right.

You hit the jackpot with your earlier post. One alters the least expensive part (sight), not the most expensive (slide). I'd suggest delaying until you get a dovetail file from Brownells. I expect the file you need is a 60 degree file (not the 65 degree file used on 1911s). These files have two safe edges and one cutting edge.

Very carefully file and try until the sight fits about half way into the dovetail. At that point, apply some cold blue to the sight, put a wee dab of grease in the dovetail and install the sight. Do your tapping on the dovetail, not on the sight blade.

Front sight pushed in 3/8 the way without fitting. Hit it in with medium blows and tightened up when it was almost centered. To get it centered it was a bit tight. Put blue loctite around it and let it sit a few min. Back sight needed a bit of filing, went in with medium blows tight all the way but not concerning tight. Blue loctite around that too. Seems a good install. Old sights pounded out hard. Needed a steel punch.

Good job! I knew you could do it all along.

Thanks! It was nice to know you believed in me lol. I'm going to let it sit a day for the loctite to cure.

I used blue loctite around the front and rear sight. Two questions. Will this hold the sights or break up after a bit? And also, Will it get into the striker safety while in liquid form?

Bit late to ask that question about the firing pin safety block isn't it?

Putting Loc-Tite in after the part goes in is generally useless unless it's the wicking Loc-Tite. Loc-Tite is intended to be between the surfaces to bond to and does so in the lack of oxygen. Given the fit you describe, it wasn't necessary. Plus, in the case of the rear sight, you're betting you got in exactly the right spot.

Well, striker safety still seems to function fine and is just as smooth so I guess I got lucky there. No harm no foul I guess. I'd clean the loctite off but I don't want to remove the sights and open the possibility again of the tritium vials cracking or not have the sights fit as well.