Re: 168 amax
In my mind, the purpose of using a frangible bullet like the amax is better suited for longer ranges and lower velocities for adequete long range expansion.
By running them at 3200 FPS and calling 600 yards as max, the AMAX is not optimum.
For that velocity and range, I would look to the ACCUBOND or Interbond or similar. Even the 180 TTSX would be a better choice. All have devent BC's and will hold together on impact at the velocities you are running them.
Now if you are talking about shots WAY out there, the AMAX starts to make sense.
If you do decide to go the route of the AMAX, concider using one with more material. At least the 178 and preferabley the 208. You will need more mass to get from one end of the critter to the other at your impact speeds.
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.