The 870 design is so simple, that if it's not ejecting, I'd look at ether a very rough chamber or (and) cheap promo shells with steel heads rather than brass.
I strip down any new or new to me gun for a clean and lube before firing a shot. It's also a good time to inspect parts.
I much prefer Wingmasters, either old or new, to the Express line. Along with a smoother action, Wingmasters don't rust at the drop of a hat. The Express "gravel blast" finish goes out of its way to rust while sitting in a row of other guns that don't.
