ok, now I have a different but related question.
in my 5.56 AR15's if I load up a subsonic 5.56 round I know it will not cycle the next round.
If I load up a subsonic 300 Whisper round the same thing happens.
why is the Whisper round supposed to work but the 5.56 round will not?
is it only a function of a heavier bullet?
