# Mossberg 500 fiber optic front sight wont line up



## KWheels (Nov 11, 2009)

I recently purchased a fiber optic bead sight for my Mossberg 500, but when i went to install it, when it was screwed all the way in, it was about 30 degrees of being lined up.

It is very similar to this model






The one i bought looked like it had been returned and stapled back shut. Unfortunatly, i bought it while on a trip, so returning it wouldnt be easy.
I am realativly sure the threads are the right ones, as the package was marked for a mossberg and it threaded right in until it didnt line up

My question to any gunsmiths out there...

Am I better off trying to find a very thin washer of sorts to make this sight line up, or by filing off a bit from the bottom of the threads? 

Im not even sure if the latter option makes sense...I dont know if the threads in the shotgun are deeper than the sights threads, and if filing it would let it sit just that little bit further in, or if the site is getting caught at the sight end, not the threads end.


I'm sure someone has seen this before...what did you do?


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## NOYDB (Nov 11, 2009)

If:

It is bottoming out and it has gone past being inline a shim might work. But you are going to have to acquire shim material, a washer probably won't work.

If: 

It is stopping short of inline, then you may have to do some fitting. Use a very fine stone to slowly, a teensy fraction at a time remove material from *the sight* bottom.

Keep in mind: 

Parts that have the screw hard fastened to them, have to be torqued into position. Ideally on small screws with fine threads they should stop 5-15 degrees short of alignment and wrist muscles only, tighten it into alignment.

So if you are fitting it, and removing material from the bottom of the sight, you are not trying to remove enough for it to line up, but to stop a few degrees short.

Fitting parts are why Gunsmiths often take longer than expected and why you should expect to pay them for their time and expertise.


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## Patchpusher (Nov 11, 2009)

If the threaded stud is not bottoming out on the barrel. You might be able to put a small wrench on the flats of the sight and turn it on in. You also could snap the bead off the threaded stud this way too. I would use a shotgun bead facing tool to trim off the bottom of the sight until it almost indexed up straight. Then degrease the threaded portion on the sight and the threaded hole in the rib. Put a small amount of BLUE locite on the threads and put it together.


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## KWheels (Nov 13, 2009)

so i need to file off the bottom of the site, not the bottom of the screw on the site?


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## Patchpusher (Nov 13, 2009)

If the screw is not bottoming out, then yes you need to clear some metal off of the bottom of the sight.


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