Lapua 338 Mag

I will pay what it takes.

Rifle is only going to be as accurate as you can shoot it. Even if the manufacturer claims 1/4 moa capable, in the real world you're probably not gonna get it. Too many variables to consider in what will make a rifle accurate. Before going with just what's the most accurate because that could be debated all day long, find a rifle that's going to fill your needs first. Is weight a concern? Adjust-ability? Ability to change calibers? Size of the rifle? What do you want to do with this thing?

Do you plan to reload? Because if you don't expect to pay at least $6 a round for decent ammo.
 
I have the AI PSR and with hand loads get better then 0.5 MOA. The PSR is the base of the new AXMC. The nice part is being able to shoot more them one caliber without buying a second rifle and scope.
 
Armalite AR-30a1, 5-shots with 250 gr load 1" at 300 yards.
The 300 gr loads shoot even better, still working on that load.
I also used other .338lm's including custom stuff and for the
money and less headaches----I'm happy.
 
Which is more accurate the Barrett 98B or MRAD?

The 98B is what I refer to as the "intro MRAD", it does not have a folding stock or the 30 MOA rail nor does it have the adjustable butt stock. As far as the accuracy between the two I would say that it would be negligible. If you want to reach out farther and have the option to be able to fit the rifle to you then the MRAD is the route you should go.