The Chinese Norinco shotguns usually are one of two types:
Copies of the Remington 870, and the Ithaca Model 37.
These were sold under a number of names, including:
Norinco.
Interstate Arms.
Brolin.
Hawk, and others.
Generally, owners of the 870 copies report they are good quality guns, and are a close enough copy that some parts will interchange, but NOT barrels.
Most owners are satisfied, and have no complaints.
These guns are NOT up to Remington standards, but make good shooters.
The Ithaca Model 37 copies have been a different story.
Many owners report that the guns are ROUGH inside, and they report having problems.
More recent imports of the Model 37 copy MAY be better quality.
Bottom line on the Norinco guns is: OK as truck guns, knock-around, and farm guns.
Always go "BOOM" when the trigger is pulled, but don't expect too much in fit and finish.
Interior of the guns, especially the Model 37 copies may be quite rough.
DO NOT count on parts interchangeability with the original American guns, and DO NOT count on accessories made for the American guns to fit.
Some MAY, but don't count on it.