I have a 870 Wingmaster with a Norinco HP9 Grizzly 14" barrel on it, see here:
I bought the HP9 first, it was alright and it worked, but it was just not quite ... smooth enough. So I bought a slightly rusty 1980s Wingmaster here on the EE, which came with a poly-choke barrel.
I swapped the barrels (they did fit, although the Wingmaster barrel was tighter on the HP9 receiver than the other way around) and sold the HP9 with the polychoke to a friend for a couple hundred bucks. The Norinco does function with the Remington barrel without issues. Other internal parts - like the bolt - aren't 100% compatible and would require some filing at least to make them fit, seems like the measurements are just slightly off. The Norinco receiver is very roughly machined on the inside compared to the old Remington.
I had the resulting 14" wingmaster refinished by Corlanes in Dawson Creek and it came out quite nice as you can see. It also required some internal repairs to the trigger group, which reminds me that I should replace the hammer pin at some point.
It is wearing an S+J Hardware 1-shot tube extension, and a nice leather shell holder that I got from a now defunct Ukrainian Ebay shop for $35 shipped. The laminate wood is off an 870 Express. I like the 14" barrel because it allows for the +1 extension flush with the barrel.
As others have mentioned, the gun as pictured did shoot at least 1 foot high at 25 yards, due to the height difference between the bead and the receiver, exaggerated by the short barrel. I wasn't able to find a taller brass bead, and I hate ghost ring sights or rear sights in general on shotguns. So finally I bought the XS-Sights "Big Dot" shotgun sight. This is a tritium illuminated dot sight, that is epoxied over the existing bead like so:
http://www.fototime.com/FB2F5DCFCED5E48/standard.jpg
Now it shoots point of aim. The Big Dot is somewhat pricey at $60 or so unfortunately.
I ended up spending more and more money on this thing gradually until it reached its current and final* form. Worth it though - it is one of my favourite guns, and comes with me whenever I'm out in the bush.
*maybe I should get it threaded for chokes?