New assault rifle for some units of the british army

[CINDERS]

Is the U.S up gunning to an 6.8mmx 51mm I wonder how the training will go with the two types of ammo the one for conflict the other for training, would love the first one for my collection it being a 2 piece case of brass and stainless steel.
As the 80,000CUP operating pressure in a brass case would see allot of ruptures I feel, but boy it must have one hell of a gas system to contain all that and without slamming the bolt out the back of the receiver.