I just bought a Mossberg 590A1 and i have been looking for a Tritium front bead. I have been searching the forum and i seen a post saying that Trijacon (Marble arms) was better than Meprolight. So im thinking about getting one but i have some questions.

How come the bead isn't listed on Trijacons website? Why do they refer to it as a Marble Arms sight when it says Trijacon right on it?

To those who are running a Tritium front bead how do you like it? Any cons to running it or only pros?

Is Tritium much better than fiber optic?

And what size threads does the Mossberg 590A1 use? i read on another post it using 5x40 but besides that i haven't seen thread size specified for the 590A1's i just want to make sure i order the right part.

I think Marble Arms and Trijicon are two different companies.

Marble Arms is over one hundred years old now and makes dovetailed sights for almost any application....I have some of their sights on one of my older rifles. They use a moose on their logo.

Trijicon is a more modern company.
But, both companies are located in Michigan, so who knows?
One company might be owned by the other by now.

Marble Arms does make a tritium shotgun bead....I've seen them on several shotguns.

Tritium is mildly radioactive and sights using tritium vials are self luminous for ~10 years or so before losing their luminosity through radioactive decay. Tritium sights are light emitters.

Fiber optic sights needs some ambient light to be luminous.....
fiber optic sights are light collectors and are not visible in total darkness.

Here is the link to the Trijacon. Marble Arms sights i am talking about http://www.brownells.com/.aspx/pid=1991 ... TGUN-SIGHT

I have been seeing them sold else where as marble arms but the sight says Trijacon right on it so im a little confused.

Only thing that i see that might be a con is the front sight looks like it could be wider than a bead sight.

Got a meprolight and like it. Might opt for the big dot on the next one. You will have to shim the meprolight or any other that is threaded. Not a big deal though. Picked up a small ss washer at ace. Not 100 percent sure the a1 is 5-40 but probably is.......
www.brownells.com/.aspx/pid=40133/Produ ... IGHT-SIGHT
doc

The bead you need will be threaded 5/40.

Tritium is a radioactive substance, and the supply is fairly tightly controlled. IIRC: Vials for sights are provided by two companies in the US: Trijicon or Meprolight, with everyone using vials from either one or the other. As a for instance, Glock's factory trit sights use Mepro vials.

Meprolight makes their own shotgun bead with their own vial.

Marble Arms makes a shotgun bead using a Trijicon vial. It is a Marbles sight that has Trijicon branded on it because of the vial.

I'm not sure where XS Sight Systems gets their vials.

I prefer tritium over fiber optics because FO require some ambient light. In an interior windowless room, FO sights are darn near useless, while trit sights will still glow.

The Marbles and Mepro beads screw in, and will need to have threads cut/trimmed off from inside of the bore. They will also need to be indexed to face the correct way. That can be accomplished via a shim (small washer), or in the case of the Marbles, there is a shoulder that can be filed down.

The XS beads (Standard Dot and Big Dot) epoxy over an existing bead. The easiest way to do it on a Mossberg is to relieve the underside so it fits over the hex base portion of the stock bead.

The Marbles and Mepro beads retail for around $30, the XS around $60.

Mepro beads come either blank (old stock?), or with a small white face surrounding the trit vial (new stock?). Marbles have a small white face surrounding the trit vial. The XS StandardDot has a small white face surrounding the trit vial. The XS BigDot has a large white face surrounding the trit vial.

I prefer the XS BigDot bead on my shotguns for a variety of reasons, but I have and have used the Marbles bead with no ill effects at 1/2 the price.

ETA: They are all larger than a stock bead. It makes little to no difference since you use the center of the bead for shooting buck, and the apex of the bead for slugs. The center of the bead doesn't really change no matter what sight you are using. The apex on all of the above is a little higher, but that isn't necessarily a bad thing. Most brands of slugs I find shoot somewhat high with a stock bead at 50 yards, as most stock beads (and slugs) are set/loaded for a 75-100 yard zero.