I've had my best accuracy with aa1680 and I think the pressure is lower. There has been much discussion on the maxi with 1680, I think the max load is 26.0, but the factory guy said they stopped at this point because of case fill, not pressure. All this is from memory....................
So, do your research and even give them a call or email.
I shot my SB1 up to max loads consistently.
One of these are 1 gr over, so use at your own risk.
Bobby