RE: 45 cal. APEX
First off ... welcome to the forum and congratulations on the new rifle. I really have no experience with the .45 caliber Apex or any other .45 caliber. If it were me with the rifle, I would get some shockwaves in .45 caliber. I would load 100 grains of powder and see how they shot. I would also get some XTP's in what every weight the .45's come in and try them also. After that I might get me some powerbelts and see how they shoot them.
What I am trying to say is, about all you can do is try different loads until you find the right one. Again, welcome and keep us posted on how the rifle is doing.