The usual reason for 22 rimfires being marked only for LR is the feeding of rounds in a repeater. Your Model 25 probably won't feed shorts and CBs from the magazine into the chamber very well. If you chamber each round by hand you should be able to shoot CBs without any safety problems. You'll want to clean the chamber well after your shooting session, because the CBs are shorter than LR and will leave residue in the chamber. You may want to try CB longs, they may feed through your normal loading system. Around here they are the same price as CB shorts.
