Remington is making ammo for it right now but it is still hard to find. Hopefully that will change in the next month or so. 6.8 uppers can be used on standard .223 lowers but require a magazine conversion kit or new magazines and new bolt. Uppers range in price from Model 1 sales at $4-500 mark, up to whatever you want to spend with options. MSTN and JTAC Supply have uppers available with Douglas Premium barrels, free float handguards, built on LMT M4 flattop upper receivers for around $1295 starting price shooting 3/4 MOA on average.