To be a very accurate shooter online or offline, all you have to do is put your gun on burst fire. It still allows you to fire at a high rate, close to full-auto but without taking away yuour accuracy. I find this works best with the G36K, and the M8 SMR. If you are also looking for accuracy and power a machine gun will deliver power but very little accuracy. For complete accuracy a sniper is the way to go, but is useless at close range. The CQC weapons are basically only good for maps where you are right in the enemy's face, and are very hard to use at long range, due to the lack of scope and power.