The searches I did didn't really find stuff for all my questions, hope this hasn't been covered too much recently.
I currently only own an Ithaca deerslayer 20 gauge, with a rifled barrel and a longer smooth bore with screw in choke tubes, that I use the few times I go deer or turkey hunting.
I'm looking for a 12 gauge to be a defensive/blasting stuff at the range/possibly hunting/shtf (although I don't really foresee that being happening) gun. Mostly defense/blasting stuff at the range.
Here are the requirements for what I'm looking for, approximately in order of importance:

12 gauge pump action
18-20in. smooth bore barrel that can shoot slugs as well as shot
>= 5+1 ammo capacity, either standard or with an extended mag tube. 7 or 8+1 would probably be ideal
chamber capable of 2 3/4in -> 3 1/2in shells
easily changed barrel
available 18-20in rifled barrel
screw in choke tubes, if this requires another barrel in addition to the first 18-20in smooth barrel that is ok
lots of aftermarket accessories both functional and cosmetic
black furniture either synthetic or black painted wood, basically something that if it gets scratched it's not a big deal and can be touched up with plain old paint or a marker
order of preference on the finish: parkerized, stainless, blued

I've been looking at the remington 870 and mossberg 590 the most, do either of these fit the bill?
Thanks

Most of your preferences are barrel-related, so for the key gun prefs of a black stock, parkerized finish, lots of aftermarket accessories, and Magnum capable, I'd look at a Remington 870 Police model.

Take a look at the Remington Law Enforcement site at:
http://www.remingtonle.com

They offer just about anything you could want in a shotgun, and the police model is the top of the line in defense shotguns.  
You have to really hunt to find a police, sheriff, State police, or federal agency that DOESN'T use the Remington 870.

Contrary to "urban myth", you CAN buy a Remington police model.  All you have to do is find a dealer that buys from a Remington LE wholesaler.  Not all Remington wholesalers are Remington >LE< wholesalers.

As an added advantage, the Police model has beefed-up springs, NO lockable safety button, and will accept all accessories without modifications.  
The standard finish is parkerized, and many guns come with the black synthetic stock.

Once you get the gun, the rest of it is picking up different barrels.

Mossberg is nice, Winchester is nice, Ithaca is nice, and they all sell guns, but the cops buy Remington 870's because they stand up, no matter what.

Or you might want to check out a 870 Express synthetic 7-shot (Remington number 5077).  I picked one up today for $300.  Yes, it has the "safety safety", but that can be retrofitted with a Wilson or Vang big safety (which is advisable on the Police too, so it doesn't really make a difference which one you get).  Other than that it's pretty much the same thing for a whole lot less money.  Heck, I've seen 'em on gunfinder.net for like $279.  I got the seven shot model so I didn't have to deal with "dimple" removal to add extra shots.  Either one is great but for the money the Synthetic 5077 is hard to beat.  FWIW, I also got this straight from Remington's FAQ.  There is no longer a difference (other than cosmetic) between the Express and the Wingmaster actions.  Kinda sad, but what can you do?  Also, lots of PD's are seeing the same cost difference and going with Express HD's.

HTH,
Rich


BTW Faris.....same number of posts as me.......creeepy

Today I bought 2 Remmington 870 Wingmaster police trade ins. 18" cyl. bore, 6 shot mags, some funiture nicks and finish wear, shot very little. $275 for the pair. I am happy.

seriously when you compare the rem.870 to
the mossy 590, this is like comparing ford to chevy. i personaly like fords and have a sweet
590 with rifle sights. i don't have a problem
with chevy or remington. either will get you from point a to b in relative comfort and style.

edited to add that being able to attach a
m7 bayo. on my 590 just adds to the cool factor.

I prefer the 870 over the 590 due to the 870 being more user friendly. The 870 disassembles alot easier and there are for more accessories for the 870. BTW, I prefer Chevies.

Edited to add: Also I prefer the 870s metal parts over the 590s plastic parts.

I have 2-18" 870 police Wingmasters and a '67 Chevy Impala SS.

hmm, I have a chevy
I think tomorrow I'll have to go to some stores that have new and used guns and do some looking and see what's available locally. still haven't fully decided but I'm kind of thinking 870
thanks for the input, and any thing else anyone wants to add

Geeez, I have a 870 with a 21" slug barrel, 8 shot mag extention, choate synthetic pistol grip stock and forend, b square receiver mount with weaver rings and a tasco pro point red dot optic ..........put me down for a heavy chevy

I have a Ford and an 870...what does that mean?

... Like this one? I know where you can get one if so.

Nothing says you care like an 870!

Remington or Mossy, either or both as in my case. Both have functioned without fail each and every time I have used them. Sorry I can't chose.

Shark, Since you state that you hunt the 870 is the clear choice.  The 870 is the king of after market barrels, sights, chokes, stocks, scopes, for hunting, target or defence. There are no hunting/ target barrels for the 590. The 870 police is a great choice to build on if money is no issue. If money is tight then the 870 home defence with the extended mag will get the job done. Mike.