So I have been thinking about a possible oddball round to do in an AR and I am interested in the 300 whisper. Does anyone have any good info on it. I know you can load it subsonic or supersonic. I have seen a switchblock type gas block for it. I would make my own brass out of 5.56. What do people use for bullets, I think they use different ones depending if they are going for subsonic or not. Anyways, experiences welcomed.