Look at what A-Zoom & other makers of .22 "snap-caps" have to say about their products. While they're usually listed under "snap caps", if you'll read the fine print they claim to be dummy rounds, to be used to check function only. I think A-Zoom's are all aluminum- no real cushion for the firing pin. Some others are all plastic. Somewhere I even read a specific warning that a few snaps on a plastic model could ruin it.
I looked into this because I wanted to do some dry-firing in my new-to-me S&W 63. My conclusion? Save empty .22 brass, & rotate it in the chamber every couple of strikes, then use a new brass.
Also: *long* ago I read somewhere about drilling a tiny "bleed hole" in the bottom center of fired .22 LR brass, then filling the case with silicone rubber. the idea was that the resilient rubber in the rim would greatly prolong the useful life of the brass case as a snap cap. True? No idea, but it would be easy & cheap for someone to try. At its worst, it would still be equal to plain empty brass hulls!
But that post above about using wall anchors?! :t That might be one heckuva good idea, & cheap to try. Hmm...