It's a very hot round. The casing itself is actually a two piece design. The bottom of the casing is crimped onto the upper portion and is made of steel alloy to be able to handle the higher pressures (80,000 PSI) The manufacturing process is actually quite amazing. The bullet will be traveling in excess of 3,200fps at the low end (They are still tinkering with the final load) and the bullet itself is also still under final design by another government contractor. It will be cool to see what the final military projectile will look like. The round that was used during testing was a Ball round. Like I have stated elsewhere, this will become the new military standard and I would not be surprised if NATO ends up adopting it as well within the next 5 years. That being said, we should start seeing more rifles chambered in that hitting the shelves in the next few years.
Also because the military will be transitioning away from the 5.56 over the next 10 years, places like Lake City will also be converting their two major manufacturing lines from 5.56 to 6.8. This will lead to an additional increase in cost for both 5.56 and 7.62x51 as both are being retired by the military over the next decade.