It happens to me sometimes that if I'm going one-on-one with someone, where we both have DMR's, and I even shoot first, connecting every shot to the head, but I'll still die.
The rare instance of that happening I will go into Theater and watch the encounter again, on both sides. It usually confirms that I got off the first shot, connecting the head shots; where he shoots after, mixing head and body shots, yet I'm the one that drops dead.
I have no explanation for it, except maybe lag, but I never have lag problems in my games. So I just think the game occasionally brain farts.
IRON MAIDEN IS MY RELIGION! Gamertag: Demigod Elessar
You're doing the right thing though in playing to your strengths- I don't have problems at medium-long range, but I always get the short end of the stick on long range/BTB range encounters with DMR/Lightrifle battles. CQC is definitely my strongest suit by far, so I try to close the gap some where if I can't use a suppressor *snicker*, I can get the kill with the carbine. It's important to practice your weaker areas though so you get better. My BR/DMR used to absolutely suck, I had a far better time using carbine and magnums, now it's decent where I can go better than 1-1 consistently.
From a CQC player, the biggest thing is gonna be landing that first shot and making it where they don't have a good angle to hose you- DMR at close range is like getting caught with your pants down if you miss that first shot. Doubly so if you're in the middle of an open hall with no cover/escape.