As a new-B, I have a couple of questions about ammo for the M&P 15 sport. 1. What ammo (5.56) produces the best penetration? 2. What is a good plinking/target ammo (also in 5.56)? As a responsible gun owner & CCW permit holder I would like to act on this before things go hay wire because of the recent shootings in Connecticut. I am trying to exercise my 2nd amendment rights.