Video demonstration: https://youtu.be/XCax3MWAXR4

TLDR: If you left click before right clicking with the classic, you will significantly increase your chance of killing the opponent while barely restraining the fire-time.

Explanation: 1 bullet of the classic does 26 body, so 3 right clicks to the body does 78. This will not be lethal even without armor. If one of these shots is a headshot you will kill someone with no armor, 2 headshots will kill anyone. However, the amount headshot is effectively left up to random chance at certain ranges. Right clicking has a significant delay before you can take any other action. This does not apply to left-clicking first. If you left click first and then right click, 4 body shots will kill an unarmored opponent and 3 bodyshots and 1 headshot will kill everybody.