Not only will it have a short barrel life but it has to be used with a silencer and is very difficult to control on full auto fire.
These issues have been brought up over and over again on various forums including FR.
My question is how are we going to get other NATO countries to adopt this? In some cases they rid themselves of a boatload of 5.45x39 Soviet to get 5.56 NATO. Now we turn around and ask them to get completely new rifles and ammo, again?
“Not only will it have a short barrel life but it has to be used with a silencer “
I think that’s what it has: it’s called a “smuzzle”