[Slater]

Other than the extended mag, heat shield, bayonet lug and a Parkerized finish, what's the significant difference between the Mossberg 500 and 590 models? Are the actions the same or do they differ?

[Andrew Wyatt]

same actions. the 590A1 has a metal triggerguard and safety. (you should replace the plastic one on the 500 with a metal one, available from brownells).

[Sir Galahad]

IIRC, the 590 also has a heavier, more heavy-duty barrel, too.

[Darrin]

than the extended mag, heat shield, bayonet lug and a Parkerized finish, My 590 has the extended mag, no heat shield, no bayo-lug, and a Marinecote finish.

[Andrew Wyatt]

my 500 has the extended mag. it doesn't have a cap on it, though. just the screw hole.

[DAL]

IIRC, doesn't the 590 have a trigger pull that is closer to a DAO trigger pull? I think I remember reading in their catalog that that was supposed to be a plus for people who carry DAO handguns. Or maybe I am hallucinating?
DAL

[mons meg]

IIRC, doesn't the 590 have a trigger pull that is closer to a DAO trigger pull? I think I remember reading in their catalog that that was supposed to be a plus for people who carry DAO handguns. Or maybe I am hallucinating?

There is a model 590DA which is identifiable by the larger triggerguard, supposedly marketed to PDs who use DAO service pistols. All other models are not this way.

[DAL]

Thanks for telling me I was wrong in such a diplomatic way. Now that you mention it, I think I do remember reading what you said somewhere. Man, 9 years of working nights and middle age is wreaking havoc with my memory.
DAL