i figure it is a decent round. sort of like the 300 whisper --just made on the much more common 5.56 case.
it preforms a lot like a 300w or 7.62x39 from what i have herd. it is a less involved swap that a 7.62x39 cause you don't need a special bolt or mags.
last i saw was $14 a box of 20
the 300B is the in thing for those running a can i'll bet. don't know what is going to happen with the round.
no matter how good a new round is it may never get common enough to be cheap.
look at the 6.5 & 6.8spc, very good rounds for the AR--do about everything better than 5.56 , less 6.5g wolf steel case ever arrives--we looking at $13 a box from now on.