what are some of the real world ballistics on the 6 mm ppc round. i can find a wide variety of foot-per-second readings, but i cant find any energy reading on the 6 mm ppc. i am wanting to see if this round will be a good addition to my ar-15 arsenal. i am planning on making an upper, and its between the 6 mm ppc and the 6.5 grendal. but, i think that with good shot placement, the 6 ppc can do the job just as well. thanks for your input, brian. , also, every one says it a wonderful 200 yard round, but is it any good farther down range?)