looks like the white box is a 45 grain crimped hollowpoint, on top of a full case of ball powder. it's the same as the bulk "military" powder they sell in some magazines, 8 pounds for however much.
i have been sorta looking into this too...my gun shoots white box pretty good too but i have found a handload that works just as well...
50 grain VMAX, Remington small rifle benchrest primer, winchester brass (leftover from white box) and 26.0 grains of Varget.
works great.
-Matt