I have had a 590a1 in the closet for a while. its the marinier model. I am looking to spruce it up to make it a fighting shotgun. I have read the pinned thread and pretty much everything is for a 870 or a winchester. I dont want a bunch of crap but maybe a side saddle, Tube extender, sights or optics, and a light.I found the info on the surefire light so I am looking for information on the other gear.

Most of the companies who make after market for the Remington also make it for the 590A1. The problem is if you have the 5 shot version, I don't think anyone makes an extended magazine thats chrome or has their marine coat. The 590A1 9 shot has a one piece long magazine. So, I think you options for that are to contact Mossberg and get a new magazine, spring, and barrel. Or buy a +2 extension from S&J Hardware and live with it being matte finished or have someone refinish it for you.

The only other recommendation would be the Magpul stock and forend and a Meprolight bead sight or similar. Makes it a lot easier to pick up the bead in stressful encounters.

I am thinking about getting the gun duracoated so I would thing the extender coud be coated also right?

I have Surefire forends for both my 870s and they are a little heavy.  You may want to think about something like a Streamlight trl-1.  It is light, you can convert it to both a pressure pad and thumb switch, and the new ones are powerful.  Make sure you mount it directly to the forend.  You may also want to think about a sling.  A lot of people are against them but I have one on all my long guns and have never had the problems others have pondered over.  I am not much on optics on a shotgun but something like a trijicon relex sight would work well.  They are built like a tank and easy to use.  Above all, get plenty of ammo and shot the hell out of it.  That may help you decide what you do and don't need.  Good luck.

Thanks, I am stopping buy the gun shop tomorrow and getting some ammo. I only have a few boxes. I like the gun the way it is but I would think a better stock, a side saddle some sights would be good. I will look at brownells.

Look into the Velcro shotgun cards for the receiver instead of a side saddle. I think they are more flexible and work great.

Pics

I will when I have time to sent the pics from my phone to a site where I can get a link and post it.