View Full Version : Installing a front night sight on Mossberg 500....

January 26, 2011, 04:17 PM
I'm a handgunner, so anything to do with shotguns is :confused: to me.

I'm wanting to replace the bead on my 500 with a tritium sight like this one http://www.impactguns.com/store/669278340449.html

Have a couple Qs:

1) How easy is it to remove the factory bead? Locking pliers and unscrew?

2) My gun is about 14 years old. Mossberg didn't change anything on their front sights (thread size, etc.) since then have they? In other words, this new tritium sight will fit my gun, right?

Thanks a bunch! :)

January 26, 2011, 04:34 PM
You can use a set of small locking pliers, beware that you'll probably bugger that brass bead up pretty bad getting it off though. That is if you ever had any intentions toward switching back.

To my knowledge they have been using the 5-40 thread pattern for quite some time. Much longer than 14 years I believe. I have a Mossberg 835 pushing 20 years old and it's 5-40 threaded if that tells you anything.

Another option in tritium beads is the Marbles unit:


It's a few dollars more but you get a white outline around the tritium insert. That will help some with daylight use.

I have the Marbles unit on an 870 and a 500 and have been happy with it on both. I will say that you may have to file off a bit of the shank once you get it installed. It was too long on mine and protruded into the barrel. Easy to remedy with a small half round file.

I have no direct experience with the Meprolight bead, but I have used Meprolight night sights on several handguns and have been pleased.

Take care,

January 26, 2011, 04:54 PM
Tom, thanks a bunch. Always appreciated the help I've gotten on TFL.

January 26, 2011, 06:19 PM
You're welcome. TFL is an excellent source of info and I've received far more than I've given.

Good luck with your sight upgrade.

hawk shooter
January 26, 2011, 07:24 PM
One thing to be aware of is that the sight will probably not line up parellel to the bore when tightened down. You can use a small nylon washer or, what I did was to wrap the barrel with two thicknesses of electrical tape and then, using some blue locktite, screw the sight in until it was parallel and tight. After letting the locktite set up overnight, I used an Xacto knife to trim away the tape from the sight base.


January 26, 2011, 07:34 PM
Mine lined up fine with no filler material, though that was something I had expected and was prepared for at installation.

January 26, 2011, 08:02 PM
Mossberg 500 front sight takes 5/32" (or 4mm) on hex. As previously stated, threads are 5-40 tpi. I replaced my original front bead with a similar one as you plan to use and I really liked it. I used the TruGlo TG948DR (red) fat bead.

January 26, 2011, 09:00 PM
Right on, guys. Thanks again for the advice. I almost asked about the possibility of the sight not screwing down so that it was pointing straight but thought it was a dumb question. ;)

January 27, 2011, 09:11 AM

One more thought: I discussed the issue with a gunsmith of the sight not lining-up straight with the barrel when screwed in. He insisted that the extra force needed to align it is OK, and that is how he installs them. I didn't do it this way because I asked the gunsmith after I already installed it with red locktight--and so it remains that way now.