I was testing SD ammo in the newly acquired Shield last week. I use GD 124+P in the G19 and Fed HST 147 in the CM9. Bought an extra 150 rounds of the GD 124+P hoping the Shield would like it and manage the recoil well. (Just to be clear not the GD SB)
Focused on accuracy at 7, 10, 15, 20 yds 1st and 2nd shot. While I was at it, I figured I'd shoot a few GDs through the CM9 in the hopes of standardizing on 1 for all. Obviously the G19 handles the +P just fine.
I have to say I was blown away (sorry, couldn't resist) by how well the Shield handled the +P round. Also tested side by side 2 shots at a time with Lawman 115gr.
Conversely, the CM9 was a beast - downright uncomfortable and inaccurate with the +P, so I will stay with the HST 147.
Bottom line is I am extremely impressed with how good the Shield feels with the +P round; as good as the G19, and much better than the CM9.
Just an observation - changes nothing of my high regard for the CM9.