I've had really good luck with IMR 7828. I've never failed to find a sub MOA load with any of the bullets I've tried when using this wonderful powder. Here is a5 shot groupI shot recently, thebullet is a140gr Nosler Ballistic Tip launched at 3350fps. It was shot on a not so good day, note the wind speeds on the target. I'm not sure if shot 3 was me or the wind but I did make a small correction after the third shot to center it up. I didn't get a picture of the 200 yard target but it was still under 2" despite the wind.
http://i23.photobucket.com/albums/b365/dmurphy317/7mm140BT.jpg
Good luck with whatever you end up with.