I don't own a SS. So some of my analysis is pure guesswork.
What magnification is your scope? If your running high magnification like 16x or 20x, any movement on your part, like breathing or heartbeats can throw off the shot if you're not practiced with shooting high magnification scopes. I have a 10X target scope on AR#1. Any movement on my part affects groups.
When I wore glasses, I had a terrible time with scopes. Without getting too technical, when I looked through my glasses, it caused a distortion that threw my shots off. Instead of looking through the center of the lens of my glasses, I was looking a little off-center.
It made the crosshairs seemed curved at the ends. As I got older and my prescription got stronger, the distortion got worse and my shooting got worse.
Contacts solved the problem. My shooting with scopes is great. My shooting with irons has dramatically improved. Having all that glass gone from my nose is a good thing too.