If you are using a hollow point bullet they tend to not feed well in this rifle and jam. Try a smoothe round nose bullet and see if that fixes it. Could be a week spring on the feed lever by the feed lips. Or could just need a good spraying with brake cleaner and a little oil.
It is a failure to eject or a failure to chamber that is causing your problem? Is it kicking the second round up, not completely chambering it or how is it jaming?
If it is not ejecting property, that could be a worn ejection spring.