[for_hire]

Rem Police Magnum
Rem Marine Magnum
Mossy 590

Which would be a good choice and why?

[zero_chances]

All of them are good. Handle each one and see which one fits you best.

[ArmedBear]

All of them, for shooting nearby targets with buckshot.
None of them, for shooting Sporting Clays.

Since all of the guns listed are excellent defensive shotguns, with many thousands of them in use by military, police and civilian shooters, it depends on why you want to make the purchase.:)

Oh, now that you edited the poll, not the 500. It's not in the same league as the others, WRT durability. It's a functional shotgun, but if I am planning to use the gun defensively, I would not choose the 500 if I had the other options available to me.

[Bob-Lee-Swagger]

Personally, I like the Marine Magnum because I like the 870 platform. However, most people like the wingmaster platform. If you like that particular platform then go for the Police Magnum