When using the DMR, if you shoot round after round repeatedly, you'll notice that the reticule on it starts to grow larger.

To decrease the chance of you missing shots after shots from rapidly pulling the trigger, just pull the trigger slowly, but not very fast like.

If you do a comparison test, you'll see when you just spray bullets every where, you miss almost all the time, but if you pull it slowly and right when the reticule starts to come back, shoot again, and you more than likely hit your target exactly where you wanted it to.

Hope it helps! And remember, counting helps to, one after the other, but not sparying it everywhere.