Wormy,
If you're going to shoot suppressed ammo through the NC-22, take a box of each with you so you can find out which ones will work your gun. On mine, the CCI 1050fps sub-sonics are the best, the Federals and the Winchesters aren't 100% reliable. We shot more than 600 through it last Sunday at Heartland and the single failure was ammo related. They were also so quiet that we had to change the stage around and shoot the rifle first - the timer wouldn't pick up the rounds, even held fairly close to the can.
The sub-sonics are more expensive (about .09 each) and I only shoot them when I need the quiet. Otherwise, I shoot standard velocity ammo through the rifle.
Don