I have a CIL/Anchutz .22 semi auto. I don't now the CIL model numder.This particuar one has a cracked reciever again. As I recall, the orginal reciever was not grooved for scope mounts, the second reciever is,probably the same as a model 520. Now I am wondering if a 525 reciever will fit. Anyone out there have experience with this type?