AA2200 is what I use now, for 20 and 25 grain loads. It has given the best accuracy, while still getting good velocity as well.
I am shooting 12.0-12.4 for the 25gr Berger Match Varmint and 13.0 for the 20gr V-Max. 25's are at 1.715 OAL and the 20's are at 1.720"