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My apology the loctite was used on the set screw for the rear sight. A youtube video the guy used a soldering iron place it on the screw and for a very short time Again good luck
 

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Discussion Starter #22
My apology the loctite was used on the set screw for the rear sight. A youtube video the guy used a soldering iron place it on the screw and for a very short time Again good luck
A soldering iron with a pin/needle point is definitely preferable since it's high and focused heat. The only pistols I've personally owned that used loctite are Glocks for the front sight. Thanks again, one way or another the current sights are coming off!
 

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I've heard of blue locktite used on the set screw for the rear sight like on my M&Ps (and most aftermarket sight manufacturers like Heine recommend it for those that use set screws), but even then I've never had any issue getting the set screw loose either. But if the FNS is like the FNX, there shouldn't be a set screw involved at all.
 

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Discussion Starter #24
I've heard of blue locktite used on the set screw for the rear sight like on my M&Ps (and most aftermarket sight manufacturers like Heine recommend it for those that use set screws), but even then I've never had any issue getting the set screw loose either. But if the FNS is like the FNX, there shouldn't be a set screw involved at all.
No set screws on either the current plain or new night sights for my 509 just press-in, both sets are FN.
 

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Thanks for the suggestions but I've never heard of loctite being used on press-in dovetail sights. I also know a hairdryer doesn't generate enough heat to soften red loctite, a heat gun for sure but then you also risk damaging the epoxy that holds the tritium vials in-place. I'll try the mechanical "push" first, if no joy then lots and lots of PB Blaster.
There was some white residue after removing the sights. Not sure if it was loctite, rocksett, or what. It might just be some funk it picked up from the parts washer but I doubt that. The 509 sights were the most difficult dovetail sights I have ever removed. I thought I was going to break the wheeler sight tool.
 

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Discussion Starter #26
Okay then, as promised, here's my findings on removing and installing FN 509 MRD Midsize sights.

Original sights were plain (no dot) suppressor height sights. Why FN chose this setup is beyond me, a topic for another time perhaps.

I purchased from MGW FN 509 Tactical sights, these are suppressor height 3-dot night sights. I had Trijicon replace the original green rear sight's tritium lamps with yellow lamps. Same life span, same brightness but a bit of contrast with the green front sight. I do this to all my night sights...YMMV

I used a Wheeler Sight Adjustment Tool, over the years I have owned and used many a sight tool the Wheeler hands down is the best for the money, git'ya one.

Slide alignment, as per gunsmithing/armorer manuals you look down the slide as if you were holding it to shoot this is how you determine left or right. In most cases on a semi-auto pistol the ejection port would face the right side.

Rear sight removal:

I attempted to remove the rear sight using the information I found searching this forum pertaining to an FNS which the 509 is supposedly based on. Post #1 indicates pushing Left to Right. Yeah, that simply was NOT going to happen. So, I pushed Right to Left and just before I was about to give up and reach for penetrating oil a very loud and disconcerting POP sound happened. Damn near scared the crap out of me wondering, what just broke? Luckily nothing and the rear sight came out from the left. FN must use a 40,000lb press to put their sights in.

Rear sight installation:

Inserting the new sight from the left side the sight slid in with no issues. I will have to fine tune it for windage at a later date but it is in for the win!

Front sight removal:

Thinking to myself okay since the rear sight went Right to Left it should stand to reason that the front sight should too. Nope! I ended up having to push the front sight out from Left to Right. Once we got our directions straight the front sight came right out.

Front sight installation:

This was a @&$><÷`@ PITA! These are suppressor height sights which means the front sight post is basically tall and thin. Any pressure applied not near enough to the bottom makes for a bending effect on the vertical axis which just ain't no good at all, NO SIR! It took some time to adjust the pushing block low enough not to bend the sight but high enough not to scrape the slide. You might need really bright lighting and a very powerful magnifying glass, I did, we're talking gnats @$$ clearances here. Oh and lo and behold the front sight would only go back in Right to Left. Go figure huh!?!

Summary:

This was not nearly as fun as I'd hoped it'd be but they're installed without damage or a scratch. I do use and will always recommend putting two layers of painters tape wherever a pushing tool makes contact with a slide, I learned this the hard way just trust me on this, O'tay!?! I didn't have to resort to heat, cold or penetrating oil which all in all is a plus. Since I am now a qualified expert at this I will gladly offer my services for the bargain basement price of $10k PER sight, you are most welcome and thankz you veddy mucho!!!
 
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It is relieving to know it was not just me. The sights were a huge pain in the ass. I wonder if there is some deformation of the sight when FN presses them in. I too had a similar pop. Did you find any residue on the sight or in the dovetail cut? I tried out my new sights on mine today and they made a HUGE difference. Mine went new sights went in like normal sights as well. I use thin (4 oz) tooling leather on each side rather than painters tape.
 

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Discussion Starter #28
You are definitely not alone, this was an unusual PITA for sights. I found no white residue I did find dried up black lubricant. I always very lightly oil the the slide cuts and sight bases before install to prevent friction binding and galling. Yeppir, that popping sound scared me, never had that happen before and was damn glad I was wearing safety glasses if a piece of metal had let loose. That tooling leather tip is a good one, I'll have to try that thanks.

My digital micrometer's battery died so I didn't deadnuts center either sight, I'll get batteries tomorrow and take care of that. I've been wanting a Ransom Rest forever once that's here I'll dial the sights in perfectly.

Just curious what sights did you go with? As written I went with FN's just with custom rear tritium color...
 

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That tooling leather tip is a good one, I'll have to try that thanks.
tooling side toward the slide...
Just curious what sights did you go with? As written I went with FN's just with custom rear tritium color...
I went with ameriglow Sig sights, SG-446. Eyeballed them and they were dead on. I went from 14 inches low at 10 yards to 2 inches low at 10 yards. Groups improved too and I credit the better sight picture along with some added familiarity. It shot well enough that the M17 may become a safe queen. Worked 100% with my Osprey as well. The sights don't clear the clocked osprey but they are right on the top of the can. Worked great and groups with the osprey were solid.
 

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Here is my 509 tactical with the new sights. Osprey is mounted for reference. The osprey gave me no real issue shooting but it does just barely occlude the top of the sight. I much prefer the sights I put on.
IMG_1284.jpg
138001
 

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Discussion Starter #31
Just curious, why did you go with non-suppressor height sights?
 

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Discussion Starter #33
Was that using a combat hold?
 

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Was that using a combat hold?
My preference is holding target on top of sight. That hold was really low at 10 yards. Holding where the front sight occludes the target was better but still really low low at 10 yards. Both were unacceptable. This was using my old formulae 147 grain (special-k) and Federal 124 grain AE. 147 grain was closer to what I expected but still off by an unacceptable margin. After the sight swap I am about 2 inches low at 5 yards (was out shooting with my daughter at "real" distance). I will get it out with a little more range soon but I am pretty certain my issue was resolved with the sight swap.
 

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Discussion Starter #35
Okay, you're using a 6 O'clock hold, FN's are combat hold. I can't remember where I saw the factory zero but I do remember it was using 124g +P ammo roughly equivalent to 124g NATO. I believe the factory zero yardage was more than 10yds too. It should have shot low with that hold and yardage but not ridiculously low.
 
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