Is there a substance I can use to coat a projectile to eliminate friction heat?
Try using carbon fiber in a uniquely woven shape. Maybe apply a dual layer with the top layer having a unique shape for heat dissipation. There have been a few carbon fiber helix designs that maintained structure and supported weight with a 2000 F acetylene/butane flame directed on it.

Another option is go with layers of powdered graphite. See if you can convert thermochemical properties with blends. Maybe you can add a coolant system for your beer can with the excess energy stored.

If you are really trying to have your beer survive extreme heat,"Thermo-electric Reactions and Currents Between Metals in Fused Salts" by Thomas Andrews is probably a good start for prototype blends. I think google has a free .pdf available through Google books. 

Here is a graph that might help with selecting your surface metals, if you ever take this project on seriously:

 

If nothing works, at least your efforts should land you a pretty hardcore beer-koozie. 

Final deciding factors come down to the degree of effort you are wishing to exert and material expense.