I had read that in general .22 WMR is more reliable than .22LR. In my personal experience this is true. I've probably put 400 - 500 rounds through my 351PD without a malfunction. Have shot many thousands of rounds of .22LR and experience maybe 3 malfunctions out of every 100 rounds fired. YMMV.
Why should the mother be forced to relinquish her firearms?