You guys will have to contact Doug, and see what he has to say about availability/price.
Again: it's an airgun. Not a .308 cartridge.....it's a .308 caliber boolit and only a .308 caliber boolit being propelled by the air around you (free propellant!). No need for powder, primer, or shells (cartridges). You can load the boolit the moment it cools from casting, step out on the back 40 and shoot the 100yard target, and immediately know the results of that boolit design before casting a couple dozen/hundred.
Now that is highly accurate shooting on the CHEAP.....no need to rush to the store when ammo is finally in stock. Make your own!