If my life was on the line, I would put it on the 870 vs. the Norinco.
See a lot of guys use the Norinco in cowboy action - and I have seen a lot of cycling/loading issues when done in a hurry or under stress. I'm sure in a self defense scenario, I will be in a hurry and under a lot of stress.
I have never seen an 870 fail to load. Worked as a trap-boy as a teen, watched literally thousands of shots, single and double, over a 5 year period with the 870, and they always performed. Out in the field, they always performed.