What do you mean you were last able to buy ammo 40Y ago?

Sorry.  I was off topic.  

Probably a combination of gouging to help recover R&D, but mostly low rate productions. I suspect poly ammo production will be like AK production. Really large capital investments, if run at high volume, cheaper guns. Don't have the volume, price goes up. As long as people don't buy, production volume will be low, keeping the price higher, less sales, thus discouraging higher volume production. 

I think TV has a contract to produce .50 BMG for the US military, for aircraft use.