I shot at box of .22 LR shotshells out of a revolver. These were the crimped variety. Then, I noticed that with regular bullets it was spraying them all over the place with no accuracy. The shotshells had leaded the barrel so severely it was now a smoothbore. It was a real pain "getting the lead out".
I assume the CCI shotshells with a clear plastic tip holding the shot may not lead a barrel like this, but don't know. I will never use the crimped .22 shotshells again.