What's the difference between the express, express magnum, wingmaster, police magnum, marine magnum, and the special purpose tactical magnum?
The Express is a "bottom of the line" budget gun, intended to sell at a price near that of the much cheaper to make cast aluminum and stamped Mossberg and Winchester.
Since the 870 still uses a forged and milled steel receiver and heavy duty fabricated parts, costs had to be cut somewhere, and what got cut was finish, and the addition of some plastic and MIM parts.
Here's the actual differences:
The Express Model has:
A plastic trigger group.
The dimples in the mag tube and the new style magazine retention system.
A rougher finish inside and outside, with some burrs left in place
A rougher blue job.
A less polished bore.
A two piece barrel. (not 100% sure about this)
Hardwood or synthetic stock, with a sporting-length fore end.
An 18", cylinder bore barrel with a bead sight or sporting barrels with screw-in chokes.
Some Metal Injection Molded (MIM) parts, like the extractor.
The Express, like all the sporting Remington's had the "J-lock" lockable safety, but this has been discontinued recently.
The 870 Police has:
An aluminum trigger group.
The old style magazine retention system.
A much smoother finish inside and out, no burrs.
A military-grade parkerized finish.
A polished bore.
A one piece barrel.
Walnut or synthetic stock, with a short police-length fore end.
Remington's new "R3" recoil pad made by Limbsaver.
Choices in different stocks, including Speed-feed, and others.
18" to 20" improved cylinder barrel, with a wide choice in sights, including rifle, ghost ring, and luminous.
Heavy-duty magazine spring.
Heavy-duty trigger-sear spring.
Sling swivel mounts.
No use of MIM parts, the extractor is milled.
The locking safety was never used on the Police.
Is a more finely finished version of the Police.
It's Remington's "top of the line" deluxe sporting gun with a polished blue finish and a chrome plated bolt.
The stock is a finer grade of walnut with Remington's famous "Bowling pin finish" in gloss or satin finish, and better checkering.
The barrels typically have a rib and screw-in chokes.
The Magnum Marine:
An Express with a factory extended magazine.
It has a synthetic stock, and the metal is nickle plated for corrosion resistance in wet conditions around boats.
The Express Magnum:
The Express and Express Magnum are the same gun. Some people just just use different terms.
After the early 1990's, ALL (or almost all) Remington shotguns are 3" Magnum guns.
There is a "Super Magnum" which uses 3 1/2" Magnum shells.
The Special Purpose Tactical Magnum is a limited production item for a big distributor.
It's just an Express with a few add-on accessories and an OD Green coating.
A one piece barrel??
I'm not 100% SURE about this, but I've seen several Express guns that appear to have two piece barrels.
The chamber and locking lug extension looks to be one piece with the actual barrel brazed into the chamber section.
I've noticed what appears to be the joint about an inch or so in front of the chamber.