Not long ago I was down at my gunsmith to see him and he show me the round and it was something to see, he told me it was made for the states that can only use straight wall.He show me a rifle that is a bolt for his brother's son he got. He told me he has people talk with him about AR's for that round and he is work on build them for them. Sound like there is many wants them in AR. He said he can build a AR cheaper then just buy the rifle. He did told me if I remember right that the round have a slit taper.