OK, to be clear, and make sure we're understanding things correctly,
rifle loads normally, fires one round, extracts and ejects the fired case normally, but does not feed another round into the chamber?
At what point does the bolt stop? Does it shut all the way but not feed another round? or does it stop with the next round part way to the chamber? or does it stop where it tries to push the next round out of the magazine??
You cleaned and oiled it, so that shouldn't be an issue, have you tried more than one magazine?
The most likely problem is a magazine issue, but its not the only possibility, just the most likely and a very easy one to test. Try another magazine (one you know works) and see if the problem goes away or changes.
Let us know what happens, (and specific details if you can).