My SW5(MP5 clone) did it extremely easy and smooth. The trigger pull is a little long but very smooth and a 30rd mag went pretty fast. I was firing from the shoulder.
We also tried my brother-in-laws 9mmAR, but it was a little more difficult. I couldn't get more than about three in a row off at one time. I went through 1 32rd mag and called it quits on that particular gun for now.
I don't know how we were grouping, we were just trying it without any targets.