My 870 Express,along with another Express and a Maverick 88 all experienced extraction problems with the cheap ammo.They all three had fired 00 buck,slugger slugs,and Express longe range #6 game loads and 3" turkey loads from Remington along with 3" turkey loads from Federal and Winchester the weekend before with no malfunctions.All these shells had steel bases.
The two 870's were cleaned by me before they were fired for the first time.I used a 10 g brush to clean the chambers and the solvents used were spray can Breakfree and Birchwood Casey gun scrubber.
After they choked on the cheap fiocchi shells I did an internet search and found several fixes ranging from 0000 steel wool or green Scotchbrite pads spun in a drill to using brake cylinder hones or simply not shooting the offending ammo.I used the steel wool method and cured the two 870's and the friend did the same to his Maverick 88 and cured it as well.
I do not know who to blame for the stuck shell problem,Rem for rough or undersized chambers(or Mossberg for the same thing on the Maverick 88)or the maker of the cheaper shells for not sizing the steel bases properly.I do know that operator error in the form of short stroking or not pumping hard enough was not a factor, nor was failing to remove any factory greases,oils,cosmoline etc that was in the chambers.
Even though I had no further extraction problems I could still see rings in the chamber and bought a FlexHone chamber hone and oil from Midway USA and after using it the chamber looks much better.
The other things that some folks did not like about 870 Expresses such as the mim extractor,J lock safety,cheap plain steel bead sight,and easily rusting finish were also cured with very inexpensive parts from Midway and the rusting was mitigated by soaking the exterior finish in Ballistil and wiping off the excess.I also bought a Shop Manual by Jerry Kuhnhausen from Midway at the same time I bought the standard safety button,gold bead bradley front sight and drill and bottoming tap to install it,forged extractor,and Scattergun tech magazine spring and follower.
I now have a shotgun that will function with the economy shells and that I have 100% confidence in.
Now if I could do something about that saw tooth vent rib