For CQB, is the HK53 effective enough? It seems that the 5.56 would trump the MP5 9mm, especially for armor penetration. But man, the HK53 is so loud. I love shooting my MP5 much more, but the 53 is sexy. But I can shoot an entire mag of 115gr thru my MP5 with no ear pro. My HK53 isn't that forgiving.