Any words on the quality, accuracy, reliability... etc. of these? The Norinko Hawk 98 is the gun in question.

General consensus on the Chinese "clone" of the Remington 870 is, A good utility, farm, truck, "knock-around" or inexpensive HD gun, but NOT up to American standards of fit or finish.

Quality is fair, and the gun always goes "BOOM" when the trigger is pulled.

Long term durability is questionable due to always suspect Chinese steels and heat treating.
No one I've heard from has used or shot enough through one to detect possible problems.

These Norinco guns were imported under a variety of names, including Norinco, various Chinese plant numbers, Hawk, Interstate Arms, Brolin, and others.

Most owners like them and have good luck with them.

On the other side, you can usually buy a good used Remington for about the same price, and have an even better gun.

"Some" parts on the Norinco will interchange with the Remington, BUT NOT ALL.
Barrels DO NOT interchange.
Many accessories made for the Remington can be used or altered to work.

Magazine extension are a problem, since the Norinco uses a longer magazine tube to hold 5 rounds, and this places the barrel support ring farther forward.
As example, a magazine extension made to be flush with an 18" Remington barrel will stick out well beyond the muzzle of the Norinco.

Bottom line: A good basic shooter, but don't expect American level quality fit and finish.
Nothing you'd want to pass on to the kids.

Any idea where I could get a mag extension that will fit. All of the web searching I've done on the Hawk 98 brings me to the Remington.  

I got a choate mag extension for an 870 off of ebay and it fits the norinco clone just fine.  I had to cut the tube down and stake the endcap in place in order for it to sit flush with the muzzle.  As far as fit and finish goes, it definitely is on par if not just a little better than the walmart special 870.  The other selling point is that it has an aluminum triggerguard as opposed to the plastic one found on true Remingtons.

Tyrone:
Do a double check on the trigger guard for us.  
The Norinco 870 clones I've seen had STEEL trigger groups.  I'd like to know if Norinco has made a change to aluminum.


nomadicwookie:
The Remington 870 extensions will screw on, but you have to do some measuring to get a good fit.
As example, an extension made for an 18" barrel will stick out beyond the muzzle on the Norinco, BUT, you could buy something like the Wilson one shot model and be OK.

If your gun has a 20" barrel, just buy an extension made for an 18".

Or as above, you can buy any extension, cut it off, weld or braze a new end cap in place, refinish it, and cut the magazine spring down to fit.