I have not run Winchester or Remington rimfire ammo, I just dont buy it. With that been said, CCI mini's, CCI SV and CCI Blazers all have function 100% as well as American Eagle. Federal bulk and Automatch have had a few failure to feed and fire issues, maybe 2 or 3 out of a 100 - 150. I see similar results with same ammo ran in my Buckmark. I shoot the .22lr conversion better!!!