I feel like I'm the only one who read this Eurogamer article a while ago. The one in which Josh Holmes states:
Eurogamer 12/11/2014
So broadly the damage is the same. Can you give me an example of a behavioural change between hip-fire and Smart Scope?
Tim Longo: Spread. Spread of bullets.
Josh Holmes: For example, the SMG, which you might have used, when you free-fire it, it has a very wide spread. When you go into Smart Scope there's a slight narrowing of the spread.
Eurogamer 12/11/2014