I'm not real clear on this, but here's my understanding:
Guns with conventional hammers can be dry-fired without harming the gun. It's less clear with striker-fired guns. Apparently some say OK, some say don't.
My GF has a Taurus PT 24/7 Pro. If you actually read the entire manual, you can find one sentence that says that dry-firing is not recommended. It's a striker gun. She dry fires it all the time, though. So far, she hasn't done it much, and I haven't said anything about it, because the jury's still out on how "bad" it is.
I've seen snap caps, but don't really understand how they work or how they're supposed to be used. Can someone elaborate on this or point me to where this is explained?
It looks like you can "fire" snap caps many times before they're "worn out". Dunno. Do you load your magazine with them and cycle them manually by racking the slide after each practice fire? They sure seem to be a PITA that discourages practice.