I was reading some of the older posts and way back in the back somewhere was a post of the dangers of dry firing the .22lr. I agree that damage can be done to the rim of the chamber and in older .22's you also risk a firing pin breakage if the firing pin is long enough to touch that chamber rim.
Well, did you know you can use hollow wall screw anchors as snap caps to protect that chamber rim ? Yep, works like a charm and cost practically nothing. Use the kind that already look like a cartridge and will separate into three fingers or so when used as a screw anchor. The white one seem to work the best or maybe the yellow ones in .22 mag and .17 rimfires. In some bolt rifles and semi auto's they will eject when the bolt is worked. Use them until the rim starts to take an indent then either turn it around a little or use a fresh one.