Tally, you shouldn't have any problem shooting Mulies with a group like that. The BOSS system does make a difference. I opted not to get it on my 7MM A Bolt, and I probably should have.
Elk, Browning still has the A and the X listed on their site with the '09 prices. It would make sense to phase out the A if the X is a lot better. I am just cautious of buying something that is new to the market when the A bolt platform has been tried and true for a very long time now.
B.R.D. Victim