RE: .17 Mach2
I am very fortunate and was able to attend the S.H.O.T. show this year and the new round was all the rage. I heard about it all over the place. The advantage is that it fits in a regular 22 action so just rebarrel your old 10-22 and go to town.
I talked to one of the hornady guys who promised a less explosive bullet in the future that wont blow a squirrel in half.