Tried Alliant 2000-MR with 190g Nosler CC bullets yesterday. Was using their load data off Noslers website. Worked up to 45.6g in LC match brass and CCI 200 primers. If you saw the 200 yard group you'd think I was lying. Measured .676" ..... I was very impressed.
Robert,
I've had great luck with the MR2K powder with 155's. Haven't really worked with the heavier bullets though.