Even with .22s the bullets used make a big difference...
You need to try several brands and use them...As a rule I don't get the best acccuracy out of the Stingers, etc...If I had one brand, I'd go with CCI Mini-Mags simply because that's what my Remington 541 and Ruger Mark II prefer...Now, my Remington 552 prefers the CCI shorts or Green Tags...

I'd pick up 3-4 different brands and give her a workout...