The rate of fire seems pretty fast on that one. Sounds like way over 850 rpm.
The owner of the gun just got the trigger pack a week or so ago. He was told it should be good for around 1200 rpm. The ammo I brought to shoot was 147gr subsonic, so I suspect it was a bit slower than 1200, but it's still fast.
Extremely controllable as well. Far more so than I assumed it was going to be, and this was my first time shooting fa.