I'm not saying it can't be done but in my opinion that is not something I would attempt unless truly desperate in a SHTF scenerio.
There is info on this forum of those who have done this with success but you must really ask yourself is it worth the risk? What would be the reward of using imporper componets? Maybe it works and nothing happens... What is the risk of using improper componets? Many things up to and including death.
As you know (hopefully) reloading is serious business and safety of yourself and others must be a first priority.
I'm a new reloader myself and yes it has been difficult to find components but it can be done. I built my list of websites i check daily to see if anything is in stock. Many of my items have been found at my LGS but I had to watch there facebook page (i'm not a member of facebook) for them to post updates of there stock. AR15.com reloading section has a very helpful thread for finding componets. Watch that thread and you will find what you need. Word of warning be quick to react when something is posted. Your competing with a huge volume of potential customers.
Hope this advice helps!