What can be causing an SKS to fail to eject? Everything is clean and the gas button is set properly. When firing the bolt only goes back about 1/2 to 2/3 of the way causing it to not eject and load the next round.
Take a .357 steel brush, and some brake cleaner. Attach your brush and cleaning rod to a drill, stuff it in the breech. Spin with break cleaner, going in and out. Cosmoline+varnish can build up in the breech, and make cases stick. Was happening to me, until I did this. Be sure to clean your breach/bore well afterwards, as if you just had a day at the range.