At this point in time, No. Not all 7.62×39 comes from Russia and the Ukraine, although a large quantity does. Also, remember that US manufacturers are producing quite a bit now. It may be more expensive, but they know a money maker when they see one. There’s many a rifle in this country using the round, so I don’t think there will be a problem for some time to come. Not saying it could never happen, but just not right now. Regardless, you should always stack it high, and stack it deep. Never forget the past.
I edited this to list some of the other countries that export 7.62×39 to the US:
These are a few of them. So don’t worry too much right now.