After trying several different brands of .22 LR ammo I have this to report about that:
CCI Mini-Mag HP doesn't shoot worth **** - 3-4 inch groups at 50 yds.
Federal 'Value Pack' (550 round box from Wal-Mart is just ok, around 2-3 inch groups at 50 yds.
old Winchester Super-X works but is filthy along with 2-3 inch groups
Ely High-speed (the box with the rabbit on the front) is good (1"-2" groups) but is pricey.
Winchester Xpert HV did pretty good also with groups about 1-1/2 to 2"
The big surprise was some Ely Standard Plus which consistently gave groups about 1/2" to 5/8" as did Lapua HP. If you can find either one of these, get some and save it for special occasions
I have had 2 failure to feeds in about 300 rounds which was probably due to a dirty magazine after shooting the old Winchester Super-X. I took the mag apart, cleaned it and have had no problems since.