I do one burst if the enemy is not moving much or at close range, but at long range (where the scope comes into play) I tend to need at least two bursts.
Then again, my accuracy is pretty awful. I reached 1000000 misses the other day
I'm somewhere around 997000 score, I never really paid attention but does match bonus affect your score on the leaderboards? Because an average match of SND will see maybe 300 score + 350 match bonus. One of my friends got 1175 score one match, 17 kills, 1 assist, 2 plants and one defuse

His score is over 2.5million and has over 20,000 wins. To think he only has 4 days more playtime than me

But dayumn.